Rancor starting P2 and P3 with Devour on cooldown

PGIII

This is not a case of not reading the tooltip. He's starting each phase off cool down. As soon as he gets up from the door, he's eaten my Rey 3 raids in a row now. VERY frustrating bug, as it totally ruins the attempt. Same thing happened on phase 3 as well.
Only thing I can think, is that since this is T7, many of us are still in P1 and 2 when they close, and that somehow bugs out the cooldown when we enter the next phase personally.