The root cause: DeploymentManager object which is recovered from respository does not come along with events property.  That implies the ORM does not invoke DeploymentManager._init_() method.

[sysadmin@controller-0 o2(keystone_admin)]$ kubectl -n orano2 logs -f o2api-c668bd5c5-2pzcx watcher

2021-11-26 02:08:58,032:[o2ims.service.auditor.dms_handler]:[dms_handler.py]-[66] [INFO]:Update a dms: 60e851e6-5342-307c-9545-abd2468e1229, name: kubernetes
2021-11-26 02:08:58,032:[o2common.service.messagebus]:[messagebus.py]-[71] [ERROR]:Exception handling command UpdateDms(data=<o2ims.domain.stx_object.StxGenericModel object at 0x7f8e7f1a7f40>, parentid='a3b86ee9-f4d4-4ae6-ab3d-ea8320f81a32')
Traceback (most recent call last):
File "/root/o2/o2common/service/messagebus.py", line 69, in handle_command
self.queue.extend(self.uow.collect_new_events())
File "/root/o2/o2app/adapter/unit_of_work.py", line 85, in _collect_new_events
while entry.events:
AttributeError: 'DeploymentManager' object has no attribute 'events'