I have encountered a problem with regeneration effects not working when you're reloading a saved game. To make the effect working again, you'll either have to remove an item from an item slot or insert an item into a slot. Any slot will do (even putting a potion into a Quick Item slot). I've tested this behavior with the Ring of Regeneration.
This issue occurs only when reloading a saved game while you're already running game. The regeneration effect works correctly when going back to the game selection screen before loading a game or after quitting and restarting the whole game.
I've attached a saved game to test the described behavior.