diff --git a/lib/crewai/src/crewai/events/event_bus.py b/lib/crewai/src/crewai/events/event_bus.py
index 9d31914f5..334138ba8 100644
--- a/lib/crewai/src/crewai/events/event_bus.py
+++ b/lib/crewai/src/crewai/events/event_bus.py
@@ -455,7 +455,7 @@ class CrewAIEventsBus:
             ...     # or future.result(timeout=5.0) in sync code
         """
         if (
-            hasattr(source, "entity_type")
+            getattr(source, "entity_type", None) in ("flow", "crew", "agent")
             and id(source) not in self._registered_entity_ids
         ):
             self.register_entity(source)