Seeing a weird mechanic on Garuda EX where a tank will get 3 stacks of spiney plume in less than 30 seconds, like 2 instantly, then it hits 3 super fast and we wipe.

It's happened randomly, double checked, and each time, the tank picking up the spiney plume had no stacks from previous phase, clean, then they go to 2, hit 3 to fast before OT's provoke is back up and wipe.

Is there some mechanic in the fight I am unaware of that causes stacks to go out faster?