To be honest, this is an epic fail by blizzard. you have an ability with no warning, no tooltip, and not on the actionbar..by our best dps pet in most circumstances that causes no end of aggrivation to the tank and group.
If you are a new warlock..go to your pet spellbook tab with your felguard/wrathguard out. If it is toggled and you are in a group TURN IT OFF.
IMHO EPIC fail blizzard..its like a cruel joke. Sorry to those I grouped with that I didnt study on all the changes..thought this was a game not a law school exam.