Whenever the game does the time-based autosave, it lowers life by one point and mana by two points if they are at max. This is with version 1.0.10.
Interesting. I posted a couple of my save files to the general 1.0.10 feedback thread, in which I'd found my characters inexplicably had far too many hit points and too much health regen. I wasn't sure what had caused the bug, though. Maybe the same autosave bug that lowers your life and mana was, under different circumstances, granting me extra life and regen?
The health loss is due to the game capping it to what it thinks is your maximum health. It's not taking into account burliness, caddishness or sagacity given from buffs.
Now life is lowered by two points instead of one. Also, there's a new problem. My counter chance is stuck at 10. It used to be higher and removing or putting on equipment with counter bonus or having the combat buffs activate does not change it.