diff --git a/desktop/src/features/collections/derivedLinks.test.mjs b/desktop/src/features/collections/derivedLinks.test.mjs
index e7da4ff931..ba1d6116ee 100644
--- a/desktop/src/features/collections/derivedLinks.test.mjs
+++ b/desktop/src/features/collections/derivedLinks.test.mjs
@@ -229,6 +229,52 @@ test("suppresses matching PR mention rows across sources but keeps unrelated cha
   );
 });
 
+test("suppresses a PR conversation without hiding another thread from the same channel source", () => {
+  const message = (eventId, threadRootId, label) => ({
+    activityType: "channel-message",
+    actorIdentity: "buzz:human",
+    authorPubkey: "human",
+    channelId: "channel-1",
+    createdAt: 1,
+    eventId,
+    kind: "thread",
+    label,
+    sourceMemberId: "channel-source",
+    threadRootId,
+    url: "",
+  });
+  const prConversation = message("pr-reply", "pr-thread", "PR chatter");
+  const unrelatedConversation = message(
+    "design-reply",
+    "design-thread",
+    "Unrelated design decision",
+  );
+  const pullRequest = {
+    ...prConversation,
+    activityType: "github-pr",
+    kind: "pull request",
+    label: "PR #7",
+    sourceEventIds: ["pr-reply"],
+    sourceMemberIds: ["channel-source"],
+    url: "https://github.com/block/buzz/pull/7",
+  };
+  const stateChange = {
+    ...pullRequest,
+    activityType: "github-pr-activity",
+    createdAt: 2,
+    kind: "PR review",
+    url: `${pullRequest.url}#pullrequestreview-1`,
+  };
+
+  assert.deepEqual(
+    projectCollectionActivity(
+      [prConversation, unrelatedConversation, pullRequest, stateChange],
+      { human: false },
+    ),
+    [unrelatedConversation, stateChange],
+  );
+});
+
 test("names channel-derived live thread provenance", () => {
   assert.equal(
     collectionChannelThreadProvenance("#design"),
diff --git a/desktop/src/features/collections/derivedLinks.ts b/desktop/src/features/collections/derivedLinks.ts
index 0f08fde0f7..5cbae89518 100644
--- a/desktop/src/features/collections/derivedLinks.ts
+++ b/desktop/src/features/collections/derivedLinks.ts
@@ -362,15 +362,22 @@ export function projectCollectionActivity(
   activity: readonly DerivedCollectionActivity[],
   actorIsAgent: Readonly<Record<string, boolean | undefined>>,
 ): DerivedCollectionActivity[] {
+  const conversationIdentity = (item: DerivedCollectionActivity) =>
+    item.channelId
+      ? `${item.channelId}:${item.threadRootId ?? item.eventId ?? item.sourceMemberId}`
+      : null;
   const pullRequestUrls = new Set(
     activity
       .filter((item) => item.activityType === "github-pr")
       .map((item) => item.url.toLocaleLowerCase()),
   );
-  const pullRequestSources = new Set(
+  const pullRequestConversations = new Set(
     activity
       .filter((item) => item.activityType === "github-pr")
-      .flatMap((item) => item.sourceMemberIds ?? [item.sourceMemberId]),
+      .flatMap((item) => {
+        const identity = conversationIdentity(item);
+        return identity ? [identity] : [];
+      }),
   );
   const pullRequestEvents = new Set(
     activity
@@ -384,7 +391,7 @@ export function projectCollectionActivity(
     ]).some((mention) => pullRequestUrls.has(mention.url.toLocaleLowerCase()));
     return (
       !mentionsResolvedPullRequest &&
-      !pullRequestSources.has(item.sourceMemberId) &&
+      !pullRequestConversations.has(conversationIdentity(item) ?? "") &&
       (!item.eventId || !pullRequestEvents.has(item.eventId))
     );
   });
diff --git a/desktop/src/features/collections/hooks.ts b/desktop/src/features/collections/hooks.ts
index af1aa63443..6aec009d88 100644
--- a/desktop/src/features/collections/hooks.ts
+++ b/desktop/src/features/collections/hooks.ts
@@ -67,7 +67,6 @@ function sourceLabel(member: CollectionMember): string {
 function messageActivity(
   member: CollectionMember,
   events: Awaited<ReturnType<typeof getChannelWindowEvents>>,
-  includePullRequests: boolean,
 ): DerivedCollectionActivity[] {
   const reference = member.reference;
   if (
@@ -102,25 +101,21 @@ function messageActivity(
         reference.type === "thread" ? reference.root_event_id : thread.rootId,
       url: "",
     };
-    const pullRequests = includePullRequests
-      ? extractGitHubPullRequestLinks([event]).map(
-          (link): DerivedCollectionActivity => ({
-            ...link,
-            activityType: "github-pr",
-            actorIdentity: `buzz:${event.pubkey.toLocaleLowerCase()}`,
-            authorPubkey: event.pubkey,
-            channelId,
-            createdAt: event.created_at,
-            eventId: event.id,
-            provenanceLabel: `${sourceLabel(member)} → mentioned PR`,
-            sourceMemberId: member.id,
-            threadRootId:
-              reference.type === "thread"
-                ? reference.root_event_id
-                : thread.rootId,
-          }),
-        )
-      : [];
+    const pullRequests = extractGitHubPullRequestLinks([event]).map(
+      (link): DerivedCollectionActivity => ({
+        ...link,
+        activityType: "github-pr",
+        actorIdentity: `buzz:${event.pubkey.toLocaleLowerCase()}`,
+        authorPubkey: event.pubkey,
+        channelId,
+        createdAt: event.created_at,
+        eventId: event.id,
+        provenanceLabel: `${sourceLabel(member)} → mentioned PR`,
+        sourceMemberId: member.id,
+        threadRootId:
+          reference.type === "thread" ? reference.root_event_id : thread.rootId,
+      }),
+    );
     return [message, ...pullRequests];
   });
 }
@@ -332,7 +327,7 @@ async function discoverCollectionMemberActivity(
       },
     );
     return {
-      items: [...threadActivity, ...messageActivity(member, messages, false)],
+      items: [...threadActivity, ...messageActivity(member, messages)],
       warnings: [],
     };
   }
@@ -344,14 +339,14 @@ async function discoverCollectionMemberActivity(
       { limit: COLLECTION_CHANNEL_DISCOVERY_LIMIT },
     );
     return {
-      items: messageActivity(member, [root, ...replies.events], true),
+      items: messageActivity(member, [root, ...replies.events]),
       warnings: [],
     };
   }
   if (member.reference.type === "message") {
     const event = await getEventById(member.reference.event_id);
     return {
-      items: messageActivity(member, [event], true),
+      items: messageActivity(member, [event]),
       warnings: [],
     };
   }
diff --git a/desktop/src/features/collections/ui/CollectionDetailScreen.tsx b/desktop/src/features/collections/ui/CollectionDetailScreen.tsx
index c5af1f4229..60f356be47 100644
--- a/desktop/src/features/collections/ui/CollectionDetailScreen.tsx
+++ b/desktop/src/features/collections/ui/CollectionDetailScreen.tsx
@@ -52,6 +52,8 @@ import {
   CollectionRowActions,
   DerivedCollectionActivityRow,
 } from "./CollectionDetailRows";
+
+const PEOPLE_PREVIEW_LIMIT = 8;
 import { CollectionGlyph } from "./CollectionGlyph";
 import { CollectionIconDialog } from "./CollectionIconDialog";
 
@@ -98,6 +100,12 @@ export function CollectionDetailScreen({
       !identity.startsWith("buzz:") ||
       !profiles[identity.slice("buzz:".length)]?.isAgent,
   );
+  const visiblePeopleIdentities = peopleIdentities.slice(
+    0,
+    PEOPLE_PREVIEW_LIMIT,
+  );
+  const hiddenPeopleCount =
+    peopleIdentities.length - visiblePeopleIdentities.length;
   const members = (data?.members ?? []).filter((member) =>
     collectionMemberMatches(member, search, type),
   );
@@ -454,7 +462,7 @@ export function CollectionDetailScreen({
                   </p>
                 </div>
                 <div className="flex flex-wrap items-center gap-2">
-                  {peopleIdentities.map((identity) => {
+                  {visiblePeopleIdentities.map((identity) => {
                     const pubkey = identity.startsWith("buzz:")
                       ? identity.slice("buzz:".length)
                       : null;
@@ -494,6 +502,11 @@ export function CollectionDetailScreen({
                       </button>
                     );
                   })}
+                  {hiddenPeopleCount > 0 ? (
+                    <span className="px-1 text-sm text-muted-foreground">
+                      +{hiddenPeopleCount} more
+                    </span>
+                  ) : null}
                   {selectedPerson ? (
                     <Button
                       onClick={() => setSelectedPerson(null)}
diff --git a/desktop/tests/e2e/collections.spec.ts b/desktop/tests/e2e/collections.spec.ts
index ec741fad4c..09e6383c8a 100644
--- a/desktop/tests/e2e/collections.spec.ts
+++ b/desktop/tests/e2e/collections.spec.ts
@@ -218,10 +218,10 @@ test("creates a collection and adds supported reference types", async ({
     });
   }, githubPullRequestUrl);
   await page.evaluate(
-    ({ failingUrl, url }) => {
+    ({ failingUrl }) => {
       window.__BUZZ_E2E_EMIT_MOCK_MESSAGE__?.({
         channelName: "general",
-        content: `Thread status for Bird Voice: ${url} and ${failingUrl}`,
+        content: `Thread status for Bird Voice: ${failingUrl}`,
         parentEventId: "mock-general-welcome",
         extraTags: [
           ["e", "mock-general-welcome", "", "root"],
@@ -229,8 +229,14 @@ test("creates a collection and adds supported reference types", async ({
         ],
       });
     },
-    { failingUrl: failingGithubPullRequestUrl, url: githubPullRequestUrl },
+    { failingUrl: failingGithubPullRequestUrl },
   );
+  await page.evaluate(() => {
+    window.__BUZZ_E2E_EMIT_MOCK_MESSAGE__?.({
+      channelName: "general",
+      content: "Unrelated channel update",
+    });
+  });
   await page.getByRole("button", { name: "Add to collection" }).click();
   await page
     .getByTestId("add-to-collection-dialog")
@@ -304,6 +310,9 @@ test("creates a collection and adds supported reference types", async ({
   await expect(page.getByTestId("collection-activity")).not.toContainText(
     "Please review",
   );
+  await expect(page.getByTestId("collection-activity")).toContainText(
+    "Unrelated channel update",
+  );
   await expect(pullRequest.getByLabel(/^Derived from /)).toBeVisible();
   await expect(pullRequest).toContainText("Live collections activity feed");
   await expect(pullRequest).toContainText("open by mock-author");