[Nightrider84]

Maybe it has something to do with rested hp regen? only thing I can think of instead of stopping at point X it keeps going on to infinity lol. Game might think you sitting and resting all the time or something.

Edit:1 So I think whats going on is there isn't really a standard Regen stat anymore. Its basically combat regen all the time. So what happens is you have a base regen of lets say 11 and you have 4000 hp's and your down to 500. What the game does is it increases it in small doses to help you regen back to your full health.
So the longer it takes to get to full health the more regen you get. I remember them introducing that early on into a few expansions because people were literally "warriors" sitting for FOREVER to get their hp back without a healer or bandages. You should notice as soon as you move your regen stat drops back to default.

Edit:2 So I just tested this on a 12 frog necro, And my base hp regen was 11 and it increased to 15,20,26 ect over time. So its increasing "based on my characters regen" by 1 point every minute or so.