I wish I could say I haven't, but it happened once.

I was doing Garuda HM for my SCH relic, everything went fine until the second phase when she summons those two minions, both minions were facing the whole party and me and the other healer (who was above i90) couldn't keep up with all the dmg DPS were getting, so we wiped. One of the DPS said he wasn't getting healed (when he was the one I was healing the most, he was eating more dmg than anyone else) the other healer argues back but we end up trying again, then we wipe again exactly at the same part, followed by another argument between the healer (defending both of us) and two dps + mt blaming us, next thing I know I'm back to open world, without saying a single word in chat other than the initial "hello".

So then took a break to understand what happened, then proceeded to report them, a GM sent me a /tell about 3 hours later and we chatted about it, I assume they got a sort of warning after that.

After I told a friend what happened he tells me that tanks were supposed to keep the adds from facing the DPS, we tried it again with him as one of the tanks and it went perfectly fine.