Thanks for your reply & suggestions. I’d however argue that this is related to the recent update and changes made in how samba does rpc calls and its interaction with apparmor.
My system was properly configured and working. This is a server providing samba services to multiple clients and no error related to shares/priviliges/permissions was ever reported.
My guess is that the update from 4.16.3-1 → 4.16.4-1 (around end of July / early August) is the culprit.
As I mentioned I have tried the apparmor solutions suggested here and they didn’t help. I will go through the list of links you shared, hoping I can get my systems up and running.
Thanks again.