In some cases there seems to be a bug when an @expires annotation is set on an event class and it is not expired by the time set in the annotation but what time it is possibly matched in a sliding window.
Fixed by https://github.com/droolsjbpm/drools/commit/53410f515b924523ff4d8dbc8babdf9f7ad983a0
Verified on BRMS 6.0.0 ER7.