Even if Endpoint monitoring feature is not in use, you see messages similar:
Aug 29 17:00:00 nsx00 2017-08-30 [user.err] 02:00:00.187 GMT ERROR TaskFrameworkExecutor-6 DBMaintainServiceImpl:331 - Removing completed EndpointMonitoringSession(s) requires a time argument Aug 29 17:00:00 nsx00 2017-08-30 [user.err] 02:00:00.186 GMT ERROR TaskFrameworkExecutor-6 EndpointMonitoringSessionDaoImpl:101 - Removing completed EndpointMonitoringSession(s) requires a time argument
VMware NSX for vSphere 6.4.x