Health (shaman spell)
 

Happened yesterday. Got this buff from a shaman, along with Sow and Regen. My hp would not go up to 100% however with these buffs. It constantly maxed out at whatever it was before the "health" buff.

So my hp bar was permanently at:
originalhp / original+health

not a big deal at level 12, not sure if it happens later.

Resolving due to age... many updates since, and could be just a display issue.