I feel you, I've had this happen. It can be harder as a party than it is solo, because multiple people failing to dodge repeatedly will buff the boss so much that it forces a wipe on everybody. That sucks when you have to repeat all the floors, not just the boss.

I think a fight isn't great if you can do everything right but be killed by other people. It's not unreasonable to ask for it to be adjusted. Dragon's Neck was a similar situation where a DPS could make a mistake with the water imps and it would punish the whole group with a knockback into the wall, until it was nerfed.