My reasoning is that you introduce the event (that causes the issue) and it seems that all the services (user/group identity, authentication) work as expected.
Based on your feedback, the issue is on SMB shares
- I don't know what SMB server you're using (you could be using stock Samba or the EoL'd Centrify Samba).
- You could have it double-joined and the system (stock samba) may not know how to deal with the DC failure
Use the Centrify website to find the proper bits and documentation.
https://www.centrify.com/express/linux-unix/download-files/