Hello!
I'm experiencing issues with Last.fm related configuration that gets randomly wiped out. Such behavior was already present in MC30, but lately, it happens even more frequently. What occurs is that the session key and username fields are both empty, and scrobbling stops working. I haven't found a pattern; sometimes it works for a month or more, and other times, it only lasts for a couple of days before it happens again.
Fortunately, I have my MC configuration backed up and can restore the Last.fm related configuration. If I restore the missing configuration data and restart the MC service, Last.fm scrobbling starts working as expected. So, I can confirm that it's not a session key related issue.
If it helps, I am currently using the MC31 shiomax/jrivermc Docker image.
Best regards