[Repro Needed]Health do not fully regenerate

It seems to only occur when I'm in a zone and using buffs that up strength/health. I don't notice it immediately, but after fighting for a while. I thought it may be related to the daytime strength bonus turning on and off, but haven't been able to pinpoint it as the 'amount' of lost health seems to fluctuate. I'm not sure how to go about testing this but if there's a recommended sequence of things you'd want us to try, I'm down for helping figure it out.