Guild Wars 2

On all dungeon bosses/pve champs ability to “magically” reset their hp bars during combat. So many times, while dps’ing them, they magically reset their healthbars (a blantant example is the Giant in Nageling). Put a global CD of several seconds on them resetting their HP during a lull in combat.

More like a bug as a side effect of anti-exploit code that most mobs have. This happens with normal mobs and veterans as well sometimes.