Nodes Credentials not retained after node-red is restarted (docker environment)

You wont get help based on that topic. Only people familiar with MSSQL will even look at it (if you're lucky).

I would suggest the issue (as it often seems to be) is docker related (or to be more accurate, your use of docker).

I say that for 2 reasons, 1, docker (if its not absolutely needed) is (IMO) just a massive pain!, 2. this does not happen on normal node-red installations.

My suspicion is the secure credentials are not being persisted (or something else is not being persisted) in the docker env.

Renamed your thread for better chance of a docker expert seeing + helping out (or just dont run in docker!)