Quote Originally Posted by FrogDog View Post
It's probably due to Divine Seal wearing off.
Several things can cause this. Divine Seal, Convalescence, anything that increases healing potency when it's applied. Essentially, regen's potency is determined on the first tick, easily testable by using divine seal. Weaker versions will not overwrite stronger versions.

Essentially, they're trying to help you out by preventing an "accidental" overwrite. I do wish that could be coded to drop it's priority over normal regens at <3 seconds, though.