diff --git a/server/src/__tests__/issues-service.test.ts b/server/src/__tests__/issues-service.test.ts
index 17d1a8ef..44ac15e6 100644
--- a/server/src/__tests__/issues-service.test.ts
+++ b/server/src/__tests__/issues-service.test.ts
@@ -150,6 +150,7 @@ describeEmbeddedPostgres("issueService.list participantAgentId", () => {
     await db.delete(projectWorkspaces);
     await db.delete(projects);
     await db.delete(goals);
+    await db.delete(heartbeatRuns);
     await db.delete(agents);
     await db.delete(instanceSettings);
     await db.delete(companies);
@@ -1159,6 +1160,68 @@ describeEmbeddedPostgres("issueService.list participantAgentId", () => {
     expect(comments.map((comment) => comment.id)).toEqual([firstCommentId]);
   });
 
+  it("lists user comments when derived run attribution scans a timestamp window", async () => {
+    const companyId = randomUUID();
+    const agentId = randomUUID();
+    const issueId = randomUUID();
+    const commentId = randomUUID();
+
+    await db.insert(companies).values({
+      id: companyId,
+      name: "Paperclip",
+      issuePrefix: `T${companyId.replace(/-/g, "").slice(0, 6).toUpperCase()}`,
+      requireBoardApprovalForNewAgents: false,
+    });
+
+    await db.insert(agents).values({
+      id: agentId,
+      companyId,
+      name: "CodexCoder",
+      role: "engineer",
+      status: "active",
+      adapterType: "codex_local",
+      adapterConfig: {},
+      runtimeConfig: {},
+      permissions: {},
+    });
+
+    await db.insert(issues).values({
+      id: issueId,
+      companyId,
+      title: "Comments issue",
+      status: "todo",
+      priority: "medium",
+    });
+
+    await db.insert(heartbeatRuns).values({
+      id: randomUUID(),
+      companyId,
+      agentId,
+      contextSnapshot: { issueId },
+      createdAt: new Date("2026-05-12T22:58:00.000Z"),
+      startedAt: new Date("2026-05-12T22:58:00.000Z"),
+      finishedAt: new Date("2026-05-12T23:14:00.000Z"),
+    });
+
+    await db.insert(issueComments).values({
+      id: commentId,
+      companyId,
+      issueId,
+      authorUserId: "user-1",
+      body: "Comment should be visible",
+      createdAt: new Date("2026-05-12T23:00:00.000Z"),
+      updatedAt: new Date("2026-05-12T23:00:00.000Z"),
+    });
+
+    const comments = await svc.listComments(issueId, {
+      order: "desc",
+      limit: 50,
+    });
+
+    expect(comments.map((comment) => comment.id)).toEqual([commentId]);
+    expect(comments[0]?.body).toBe("Comment should be visible");
+  });
+
   it("includes blockedBy summaries on list rows in one batched pass", async () => {
     const companyId = randomUUID();
     const blockerId = randomUUID();
diff --git a/server/src/services/issues.ts b/server/src/services/issues.ts
index 1e8f1f9b..7a708c28 100644
--- a/server/src/services/issues.ts
+++ b/server/src/services/issues.ts
@@ -1943,6 +1943,11 @@ export function issueService(db: Db) {
     }, null);
     if (minCommentCreatedAtMs === null || maxCommentCreatedAtMs === null) return comments;
 
+    const minCommentCreatedAt = new Date(minCommentCreatedAtMs).toISOString();
+    const maxCommentCreatedAt = new Date(
+      maxCommentCreatedAtMs + ISSUE_COMMENT_RUN_LOG_DERIVATION_END_SLACK_MS,
+    ).toISOString();
+
     const runs = await db
       .select({
         runId: heartbeatRuns.id,
@@ -1969,8 +1974,8 @@ export function issueService(db: Db) {
                 and ${activityLog.runId} = ${heartbeatRuns.id}
             )`,
           ),
-          sql`coalesce(${heartbeatRuns.finishedAt}, ${heartbeatRuns.createdAt}) >= ${new Date(minCommentCreatedAtMs)}`,
-          sql`coalesce(${heartbeatRuns.startedAt}, ${heartbeatRuns.createdAt}) <= ${new Date(maxCommentCreatedAtMs + ISSUE_COMMENT_RUN_LOG_DERIVATION_END_SLACK_MS)}`,
+          sql`coalesce(${heartbeatRuns.finishedAt}, ${heartbeatRuns.createdAt}) >= ${minCommentCreatedAt}::timestamptz`,
+          sql`coalesce(${heartbeatRuns.startedAt}, ${heartbeatRuns.createdAt}) <= ${maxCommentCreatedAt}::timestamptz`,
         ),
       )
       .orderBy(desc(heartbeatRuns.createdAt));