1. 0.5.3.4a
2. 64 bit Windows 8.1 Pro
3. One of my favorite servants suddenly loses energy constantly and is now stuck at 0, even after resting for 2 or 3 days.
4. N/A
5. Tried selling him to the slave guild and buying him back, which didn't help.
EDIT: I moved him to a personal room and clicked on "kissing" in the sex menu, since it's the lowest energy option, and something I did seems to have fixed it.