Garuda story mode appears to be bugged.

Had a decent DF group for a change, everyone did everything the way they were supposed to - we had a tall pillar saved for the last big AoE, the tank hit his LMB just before, everyone was topped off and behind the pillar, Feathers were long dead. The AoE hit the tank for around 2k damage, the rest of us on the order of 2300 (my hp is around 1990, just or reference). We had done this twice, just to be sure we were getting everything right. We were.

This amount of damage is, according to the healers we've spoken to, is near triple what it used to be when they'd done the fight. What's going on?