I think most people and developers know about this problem, but since it isn't reported here I will report it.
How it works: 1. The raid starts boss encounter, let's say Illidan. 2. Player fucked up and died by Illidan's Eye Beam. 3. He is ressurected by Combat Ress by druid. 4. He stand up AND he ISN'T in COMBAT. It won't reapply until the player takes action to attack the boss or heal player in combat. Which makes it a Critical bug, cause ressurected player without combat can just stand back and be casting ressurection on fallen comrades, making the boss a joke not an hard encounter. It does work like that for EVERY encounter, no matter how easy or hard it is.