Yeah, I haven't had much time to play recently, but I noticed something similar this morning. It appears that unloaded vessels just draw down their batteries in the background without ever using their solar panels to recharge. I didn't notice this earlier since my current game only has one space station in it and that has altogether too much battery capacity.
If you switch to the vessel the batteries charge as normal and the problem is resolved, but there seems to be some sort of issue related to electricity remaining. I'll try to get some logs later today when I get back from Canada Day festivities.
Other than this issue, I have not had any other problems.
Edit: I had a few minutes so I reinstalled KSP and created a ticket: https://github.com/KSP-RO/TacLifeSupport/issues/92
After a bit more testing, reinstalling BackgroundProcessing appears to resolve the problem. I will need to do a bit more testing, and will try to report back later today.
https://github.com/JPLRepo/background-processing/releases/tag/v0.4.5.0