After upgrade to 10.5.x both MOM & Collector logs contain repeated messages:
SEVERE: Could not synchronize database state with session
org.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect): [com.timestock.tess.data.objects.Monitor#700000000000002563]
If enable DEBUG this line is also visible before the SEVERE message:
[DEBUG] [pool-19-thread-1] [Manager.com.wily.apm.tess.isengard.EMBizRecordingServiceBean] disabling agent monitor in db...