diff --git a/src/heap/cppgc/pointer-policies.cc b/src/heap/cppgc/pointer-policies.cc
index 0000000..0000000 100644
--- a/src/heap/cppgc/pointer-policies.cc
+++ b/src/heap/cppgc/pointer-policies.cc
@@ -108,7 +108,15 @@ namespace internal {

 PersistentRegion& StrongPersistentPolicy::GetPersistentRegion(
     const void* object) {
-  return BasePage::FromPayload(object)->heap().GetStrongPersistentRegion();
+  auto& heap = BasePage::FromPayload(object)->heap();
+  if (V8_UNLIKELY(!heap.CurrentThreadIsHeapThread())) {
+    fprintf(stderr,
+            "POCTRACE *** OFF-THREAD StrongPersistent FreeNode: object=%p "
+            "heap=%p cur_tid=%d ***\n",
+            object, &heap, v8::base::OS::GetCurrentThreadId());
+    fflush(stderr);
+  }
+  return heap.GetStrongPersistentRegion();
 }

 PersistentRegion& WeakPersistentPolicy::GetPersistentRegion(