diff --git a/src/core/events.py b/src/core/events.py
index 74aca24be94716272caa7ae8327ce8ada5d1c9ed..6f2e20bfcc45e52f4105a40b08aef96ec26056aa 100644
--- a/src/core/events.py
+++ b/src/core/events.py
@@ -27,6 +27,7 @@ from src.plugins.mailer         import AuraMailer
 from src.plugins.monitor        import AuraMonitor
 from src.plugins.trackservice   import TrackServiceHandler
 from src.scheduling.fallback    import FallbackManager
+from src.scheduling.models      import DB
 
 
 class EventBinding():
@@ -303,6 +304,7 @@ class EngineEventDispatcher():
             self.logger.debug("on_fallback_active(..)")
             self.call_event("on_fallback_active", timeslot, fallback_type)
 
+        DB.session.expunge(timeslot)
         thread = Thread(target = func, args = (self, timeslot, fallback_type))
         thread.start()