diff --git a/packages/client-runtime/src/state/threadInbox.ts b/packages/client-runtime/src/state/threadInbox.ts
index 43294c02a9b40..09043c7d35ade 100644
--- a/packages/client-runtime/src/state/threadInbox.ts
+++ b/packages/client-runtime/src/state/threadInbox.ts
@@ -123,7 +123,7 @@ export function createInboxReturnTracker() {
   const keyOf = (thread: ThreadKeyInput) => `${thread.environmentId}:${thread.id}`;
   const states = new Map<
     string,
-    { working: boolean; deadline: number | null; placement: string }
+    { working: boolean; deadline: number | null; placement: string | null }
   >();
   const returns = new Map<string, number>();
   const listeners = new Set<() => void>();
@@ -184,17 +184,21 @@ export function createInboxReturnTracker() {
       for (const thread of threads) {
         const key = keyOf(thread);
         present.add(key);
-        const placement = JSON.stringify([
-          thread.archivedAt,
-          thread.deletedAt,
-          thread.pinnedAt,
-          thread.settledOverride,
-          thread.settledAt,
-          thread.snoozedAt,
-          thread.snoozedUntil,
-          thread.activeOrderKey,
-        ]);
         const previous = states.get(key);
+        const actual = isThreadWorking(thread);
+        const placement =
+          actual || previous?.working
+            ? JSON.stringify([
+                thread.archivedAt,
+                thread.deletedAt,
+                thread.pinnedAt,
+                thread.settledOverride,
+                thread.settledAt,
+                thread.snoozedAt,
+                thread.snoozedUntil,
+                thread.activeOrderKey,
+              ])
+            : null;
         const actionable =
           thread.hasPendingApprovals ||
           thread.hasPendingUserInput ||
@@ -210,7 +214,6 @@ export function createInboxReturnTracker() {
           thread.pinnedAt != null ||
           thread.settledOverride === "settled" ||
           effectiveSnoozed(thread, { now: observedAt });
-        const actual = isThreadWorking(thread);
         // Only shelf placement is held: execution state and attention requests stay authoritative.
         const deadline =
           !actual && previous?.working && !actionable && !moved && !excluded