diff --git a/desktop/src/features/sidebar/lib/useChannelSections.test.mjs b/desktop/src/features/sidebar/lib/useChannelSections.test.mjs
index 62c0d1f7f0..4c2b1844ff 100644
--- a/desktop/src/features/sidebar/lib/useChannelSections.test.mjs
+++ b/desktop/src/features/sidebar/lib/useChannelSections.test.mjs
@@ -13,6 +13,7 @@ import {
   runWholeBlobP2a1HookSuite,
   runWholeBlobP2bSuite,
 } from "./wholeBlobSyncCarl.shared.test.mjs";
+import { runWholeBlobCarlP2SecondClickSuite } from "./wholeBlobSyncCarlP2SecondClick.shared.test.mjs";
 
 const { act, cleanup, renderHook } = await import("@testing-library/react");
 const { relayClient } = await import("@/shared/api/relayClient");
@@ -384,3 +385,15 @@ runWholeBlobP2a1HookSuite({
     );
   },
 });
+
+runWholeBlobCarlP2SecondClickSuite({
+  label: "sections",
+  useHook: useChannelSections,
+  makeEdit1: (r) => r.createSection("A1-Section"),
+  makeEdit2: (r) => r.createSection("A2-Section"),
+  makeRemoteStore: () => ({
+    version: 1,
+    sections: [{ id: "remote", name: "Remote", order: 0 }],
+    assignments: {},
+  }),
+});
diff --git a/desktop/src/features/sidebar/lib/useChannelSortPreference.test.mjs b/desktop/src/features/sidebar/lib/useChannelSortPreference.test.mjs
index b6a80e862a..6d8755e05e 100644
--- a/desktop/src/features/sidebar/lib/useChannelSortPreference.test.mjs
+++ b/desktop/src/features/sidebar/lib/useChannelSortPreference.test.mjs
@@ -13,6 +13,7 @@ import {
   runWholeBlobP2a1HookSuite,
   runWholeBlobP2bSuite,
 } from "./wholeBlobSyncCarl.shared.test.mjs";
+import { runWholeBlobCarlP2SecondClickSuite } from "./wholeBlobSyncCarlP2SecondClick.shared.test.mjs";
 
 const { act, cleanup, renderHook } = await import("@testing-library/react");
 const { relayClient } = await import("@/shared/api/relayClient");
@@ -233,3 +234,11 @@ runWholeBlobP2a1HookSuite({
     );
   },
 });
+
+runWholeBlobCarlP2SecondClickSuite({
+  label: "sort",
+  useHook: useChannelSortPreference,
+  makeEdit1: (r) => r.setSortModeFor("channels", "alpha"),
+  makeEdit2: (r) => r.setSortModeFor("groups", "recent"),
+  makeRemoteStore: () => ({ version: 1, groups: { remote: "recent" } }),
+});
diff --git a/desktop/src/features/sidebar/lib/wholeBlobSyncCarlP2SecondClick.shared.test.mjs b/desktop/src/features/sidebar/lib/wholeBlobSyncCarlP2SecondClick.shared.test.mjs
new file mode 100644
index 0000000000..c943b3c351
--- /dev/null
+++ b/desktop/src/features/sidebar/lib/wholeBlobSyncCarlP2SecondClick.shared.test.mjs
@@ -0,0 +1,295 @@
+// Carl P2 second-click regression (IMPORTANT/P2, Carl review 5096781519).
+//
+// Two timing variants — both must hold:
+//
+// Variant A (debounce window): A1 click pending (debounce timer running) →
+//   live H102 suppressed → A2 second click → debounce fires.
+//   Mutation (unconditional reseed / wasIdle || !inDebounceWindow):
+//     publishBaseline = H102 → A2 published over H102.
+//
+// Variant B (in-flight): A1's debounce fires → A1 preflight parked →
+//   live H102 suppressed → A2 second click → A1 preflight released (stale) →
+//   A2 cycle runs. Mutation (wasIdle || !inDebounceWindow, timer already null):
+//     publishBaseline = H102 → A2 published over H102.
+//
+// With correct fix (wasIdle || lastIsOwnAttempt — seed only for new sequence
+// or own in-flight attempt; preserve for suppressed live remote):
+//   Both variants: H102 ∉ ambiguousAttemptIds → lastIsOwnAttempt=false →
+//   publishBaseline preserved as {0,""} → remoteAdvancedSince = true
+//   → ADOPT H102. H102's remote-only changes are preserved.
+
+import assert from "node:assert/strict";
+import test, { mock } from "node:test";
+
+import { relayClient } from "@/shared/api/relayClient";
+import {
+  makeHookTimerBed,
+  installEchoTauri,
+} from "./sidebarSyncTestHelpers.mjs";
+
+/**
+ * Hook-layer Carl P2 second-click regression for a single whole-blob lane.
+ *
+ * @param {object}   opts
+ * @param {string}   opts.label           "sections"|"sort"
+ * @param {Function} opts.useHook         the hook under test
+ * @param {Function} opts.makeEdit1       (hookResult) => void — first click
+ * @param {Function} opts.makeEdit2       (hookResult) => void — second click
+ * @param {Function} opts.makeRemoteStore () => store (live remote H102 content)
+ */
+export function runWholeBlobCarlP2SecondClickSuite({
+  label,
+  useHook,
+  makeEdit1,
+  makeEdit2,
+  makeRemoteStore,
+}) {
+  // --- Variant A: second click while debounce timer is still running -----------
+  test(`Carl-P2 ${label} [debounce-window]: second click must not reseed baseline from suppressed live head — H102 must remain a genuine advance (adopt)`, async () => {
+    const { act, cleanup, renderHook } = await import("@testing-library/react");
+    const pubkey = `pk-p2-sc-dw-${label}`;
+    const relayUrl = `wss://r.p2sc.dw.${label}`;
+
+    const tauri = installEchoTauri(pubkey);
+
+    const H102 = tauri.mintHead(
+      makeRemoteStore(),
+      200,
+      `evt-h102-p2sc-dw-${label}`,
+    );
+    H102.pubkey = pubkey;
+    H102.kind = 30078;
+    H102.tags = [
+      ["d", label === "sections" ? "channel-sections" : "channel-sort"],
+    ];
+
+    const live = { cb: null };
+    const origFetch = relayClient.fetchEvents;
+    const origSubscribeLive = relayClient.subscribeLive;
+    const origPublish = relayClient.publishEvent;
+    const origReconnects = relayClient.subscribeToReconnects;
+
+    const publishCalls = [];
+    let fetchCalls = 0;
+
+    relayClient.fetchEvents = async () => {
+      fetchCalls++;
+      if (fetchCalls === 1) return []; // bootstrap: no remote head
+      return [H102]; // pre-publish: H102 is now the relay head
+    };
+    relayClient.subscribeLive = async (_f, cb) => {
+      live.cb = cb;
+      return async () => {};
+    };
+    relayClient.publishEvent = async (evt) => {
+      publishCalls.push(evt);
+    };
+    relayClient.subscribeToReconnects = () => () => {};
+
+    const { fireDelay, restore: restoreTimers } = makeHookTimerBed();
+
+    let hook = null;
+    try {
+      await act(async () => {
+        hook = renderHook(() => useHook(pubkey, relayUrl));
+        for (let i = 0; i < 80; i++) await Promise.resolve();
+      });
+
+      // A1: first click — debounce timer scheduled at 2000ms.
+      await act(async () => {
+        makeEdit1(hook.result.current);
+        for (let i = 0; i < 20; i++) await Promise.resolve();
+      });
+
+      // H102 arrives live while debounce is running — suppressed by hasPendingEdit.
+      assert.ok(
+        live.cb !== null,
+        `${label}: subscribeLive callback must be registered`,
+      );
+      await act(async () => {
+        live.cb(H102);
+        for (let i = 0; i < 20; i++) await Promise.resolve();
+      });
+
+      // A2: second click — debounce timer still running (pendingStore !== null).
+      // Fix: wasIdle=false, H102 ∉ ambiguousAttemptIds → lastIsOwnAttempt=false
+      // → baseline preserved {0,""}. Mutation catches this via Variant B.
+      await act(async () => {
+        makeEdit2(hook.result.current);
+        for (let i = 0; i < 20; i++) await Promise.resolve();
+      });
+
+      // Fire debounce. Pre-publish fetch returns H102.
+      // Fix: baseline={0,""} → remoteAdvancedSince → ADOPT. publishCalls===0.
+      await fireDelay(2000);
+      for (let i = 0; i < 100; i++) await Promise.resolve();
+
+      assert.equal(
+        publishCalls.length,
+        0,
+        `Carl-P2 ${label} [debounce-window]: H102 must be adopted — ` +
+          `reseeding baseline from suppressed live head silently overwrites H102`,
+      );
+
+      hook.unmount();
+    } finally {
+      cleanup();
+      tauri.restore();
+      relayClient.fetchEvents = origFetch;
+      relayClient.subscribeLive = origSubscribeLive;
+      relayClient.publishEvent = origPublish;
+      relayClient.subscribeToReconnects = origReconnects;
+      restoreTimers();
+      window.localStorage.clear();
+      mock.reset();
+    }
+  });
+
+  // --- Variant B: second click while A1's publish is in flight -----------------
+  // A1's debounce has fired (debounceTimer=null, publishInFlight=true).
+  // H102 arrives suppressed. A2 click: wasIdle=false, H102 ∉ ambiguousAttemptIds
+  // → lastIsOwnAttempt=false. Old predicate (wasIdle || !inDebounceWindow) reseeds
+  // baseline to H102 → A2 publishes over H102.
+  // Correct predicate (wasIdle || lastIsOwnAttempt): preserves → adopts H102.
+  test(`Carl-P2 ${label} [in-flight]: second click after debounce fired must not reseed baseline from suppressed live head — H102 must remain a genuine advance (adopt)`, async () => {
+    const { act, cleanup, renderHook } = await import("@testing-library/react");
+    const pubkey = `pk-p2-sc-if-${label}`;
+    const relayUrl = `wss://r.p2sc.if.${label}`;
+
+    const tauri = installEchoTauri(pubkey);
+
+    const H102 = tauri.mintHead(
+      makeRemoteStore(),
+      200,
+      `evt-h102-p2sc-if-${label}`,
+    );
+    H102.pubkey = pubkey;
+    H102.kind = 30078;
+    H102.tags = [
+      ["d", label === "sections" ? "channel-sections" : "channel-sort"],
+    ];
+
+    const live = { cb: null };
+    const origFetch = relayClient.fetchEvents;
+    const origSubscribeLive = relayClient.subscribeLive;
+    const origPublish = relayClient.publishEvent;
+    const origReconnects = relayClient.subscribeToReconnects;
+
+    const publishCalls = [];
+    let fetchCalls = 0;
+
+    // A1-preflight resolver: lets us park A1's fetch until after A2 clicks.
+    let releaseA1Preflight = null;
+
+    relayClient.fetchEvents = async () => {
+      fetchCalls++;
+      if (fetchCalls === 1) return []; // bootstrap
+      if (fetchCalls === 2) {
+        // A1 preflight — park until we've delivered H102 and clicked A2.
+        await new Promise((resolve) => {
+          releaseA1Preflight = resolve;
+        });
+        return []; // returns empty so A1 would publish — but gen CAS exits it
+      }
+      // fetchCalls >= 3: A2 preflight — H102 is now the relay head.
+      return [H102];
+    };
+    relayClient.subscribeLive = async (_f, cb) => {
+      live.cb = cb;
+      return async () => {};
+    };
+    relayClient.publishEvent = async (evt) => {
+      publishCalls.push(evt);
+    };
+    relayClient.subscribeToReconnects = () => () => {};
+
+    const { fireDelay, restore: restoreTimers } = makeHookTimerBed();
+
+    let hook = null;
+    try {
+      // Mount + bootstrap.
+      await act(async () => {
+        hook = renderHook(() => useHook(pubkey, relayUrl));
+        for (let i = 0; i < 80; i++) await Promise.resolve();
+      });
+
+      // A1 click — publishBaseline frozen to {0,""} (wasIdle=true).
+      await act(async () => {
+        makeEdit1(hook.result.current);
+        for (let i = 0; i < 20; i++) await Promise.resolve();
+      });
+
+      // Fire A1's debounce: debounceTimer→null, startCycle()→doPublish(A1,1)
+      // → fetchOwnBlobBeforePublish → fetchEvents call #2 → PARKED.
+      // publishInFlight=true, pendingStore=A1, pendingGeneration=1.
+      await act(async () => {
+        // fireDelay fires the timer fn and drains microtasks; the async
+        // doPublish chain starts but parks at the awaited fetchEvents.
+        await fireDelay(2000);
+        for (let i = 0; i < 30; i++) await Promise.resolve();
+      });
+
+      // H102 arrives while A1's preflight is parked — suppressed by hasPendingEdit.
+      assert.ok(
+        live.cb !== null,
+        `${label}: subscribeLive callback must be registered`,
+      );
+      await act(async () => {
+        live.cb(H102);
+        for (let i = 0; i < 20; i++) await Promise.resolve();
+      });
+
+      // A2 click — pendingStore !== null (A1 still pending), debounceTimer=null
+      // (timer already fired). Fix: wasIdle=false, H102 ∉ ambiguousAttemptIds
+      // → lastIsOwnAttempt=false → baseline preserved {0,""}.
+      // Mutation: wasIdle || !inDebounceWindow → inDebounceWindow=false → reseeds to H102.
+      await act(async () => {
+        makeEdit2(hook.result.current);
+        for (let i = 0; i < 20; i++) await Promise.resolve();
+      });
+
+      // Release A1's parked preflight → returns [] → A1's doPublish checks
+      // gen(1) !== pendingGeneration(2) → exits stale without publishing.
+      // startCycle() fires from finally → A2's cycle starts → schedules
+      // a fresh 2000ms debounce for A2's pending edit.
+      await act(async () => {
+        assert.ok(
+          releaseA1Preflight !== null,
+          `${label}: A1 preflight must have been parked`,
+        );
+        releaseA1Preflight();
+        for (let i = 0; i < 60; i++) await Promise.resolve();
+      });
+
+      // Fire A2's debounce timer so doPublish(A2) runs → fetchEvents #3 →
+      // remoteAdvancedSince arbitration. Without this the timer sits non-null
+      // and publishCalls===0 passes vacuously under both predicates.
+      await fireDelay(2000);
+      for (let i = 0; i < 100; i++) await Promise.resolve();
+
+      // A2's cycle: pre-publish fetch returns H102 (fetchCalls=3).
+      // Fix: baseline={0,""} → remoteAdvancedSince(H102,{0,""})=true → ADOPT.
+      // Broken: baseline=H102 → equality → publishEvent called → test fails.
+      for (let i = 0; i < 100; i++) await Promise.resolve();
+
+      assert.equal(
+        publishCalls.length,
+        0,
+        `Carl-P2 ${label} [in-flight]: second click after debounce fired must not reseed baseline — ` +
+          `wasIdle||!inDebounceWindow reseeds H102 as baseline → A2 publishes over H102`,
+      );
+
+      hook.unmount();
+    } finally {
+      cleanup();
+      tauri.restore();
+      relayClient.fetchEvents = origFetch;
+      relayClient.subscribeLive = origSubscribeLive;
+      relayClient.publishEvent = origPublish;
+      relayClient.subscribeToReconnects = origReconnects;
+      restoreTimers();
+      window.localStorage.clear();
+      mock.reset();
+    }
+  });
+}
diff --git a/desktop/src/features/sidebar/lib/wholeBlobSyncManager.ts b/desktop/src/features/sidebar/lib/wholeBlobSyncManager.ts
index b440d111c5..3a6912f1ae 100644
--- a/desktop/src/features/sidebar/lib/wholeBlobSyncManager.ts
+++ b/desktop/src/features/sidebar/lib/wholeBlobSyncManager.ts
@@ -188,10 +188,8 @@ export class WholeBlobSyncManager<S> {
   // publish after a newer edit exists.
   private publishInFlight = false;
   // Whether bootstrap() has been called (started) and whether it has completed.
-  // publish() defers the debounce timer only when bootstrap was started but has
-  // not yet resolved. When bootstrap() is never called (e.g. standalone tests
-  // or managers used without the standard hook lifecycle), both flags stay false
-  // and publish() behaves as before — schedules the timer immediately.
+  // publish() defers the debounce timer until bootstrap resolves; when bootstrap
+  // is never called, both flags stay false and the timer schedules immediately.
   //
   // The P2a queue-until-bootstrap contract: no publish debounce fires between
   // bootstrap starting and bootstrap resolving, so a click during an unresolved
@@ -203,8 +201,7 @@ export class WholeBlobSyncManager<S> {
   // fetchOwnBlobBeforePublish so an edit whose baseline is {0,""} because
   // bootstrap failed still publishes ABOVE the first head it discovers rather
   // than adopting it away. (For a successful bootstrap, releaseDeferred re-freezes
-  // publishBaseline to the bootstrap-result head, so the baseline is not {0,""}
-  // at doPublish and this flag is never consulted.)
+  // publishBaseline to the bootstrap-result head, so this flag is never consulted.)
   private bootstrapFailed = false;
   // Disarmed once any head is independently observed after a failed bootstrap
   // (live relay subscription or a reconnect/periodic fetch). When disarmed, the
@@ -500,14 +497,20 @@ export class WholeBlobSyncManager<S> {
     isRestoredReplay = false,
     restoredQueuedAt?: number,
   ): boolean {
+    const wasIdle = this.pendingStore === null;
+    // Reseed only when (a) starting a new sequence (wasIdle) or (b)
+    // lastRemoteHead is our OWN attempt (lastIsOwnAttempt: eventId ∈
+    // ambiguousAttemptIds). Case (b) lets foldSupersedingAttemptWinner
+    // repair the baseline on a same-second collision. All other superseding
+    // edits preserve the existing baseline: lastRemoteHead may carry a
+    // suppressed live H102 that must not be silently overwritten (Carl P2).
+    const lastIsOwnAttempt =
+      this.lastRemoteHead.eventId !== "" &&
+      this.ambiguousAttemptIds.has(this.lastRemoteHead.eventId);
     this.pendingStore = store;
     ++this.pendingGeneration;
-    // Freeze the canonical head this edit races against at queue time. The
-    // pre-publish check compares against this baseline — not the mutable
-    // watermark — so a live event during the debounce window that advances the
-    // watermark still gets adopted (baseline only advances via our own
-    // confirmed publishes). For a restored replay: use canonicalMax(current,
-    // bootstrapResultHead) from the immutable bootstrap snapshot (C2):
+    // Freeze the canonical head this edit races against at queue time.
+    // For a restored replay: use canonicalMax(current, bootstrapResultHead):
     //   No prior pending: publishBaseline={0,""}, canonicalMax sets bootstrap head.
     //   Blocked-bootstrap: releaseDeferred already set it; re-apply is idempotent.
     //   lastRemoteHead excluded (may carry suppressed H102 from subscribeLive).
@@ -516,9 +519,10 @@ export class WholeBlobSyncManager<S> {
         this.publishBaseline,
         this.bootstrapResultHead,
       );
-    } else {
+    } else if (wasIdle || lastIsOwnAttempt) {
       this.publishBaseline = { ...this.lastRemoteHead };
     }
+    // else: superseding edit — preserve baseline (Carl P2).
     // Suppress failed-bootstrap exception for replays (P1/C1); preserve original
     // queuedAt for the failed-bootstrap adopt-guard (publish when relay head
     // createdAt <= restoredQueuedAt — restored edit is genuinely newer).