I've been having the same issue. A vampire joined my clan and after a few days of play I noticed that he was never resetting from a night shift. I took away his vampire and added it back in. Next day he was fine and his energy reset like normal.

Couple play days later and he's full rest mode and daylight doesn't hurt him at all.

To be honest, I'm thinking it started when I started using the unstable build but even if I switch back he still operates in full power mode..

lol Blade