Yep, she was bugged like this for most of beta. Saw it on multiple streams and my guild encountered it ourselves as well during our time on beta.
We tried to just play around the bug eventually having everyone stack in the center of the room before beams came out since it seemed to kill people who were just too close to the sides however this didn’t work at all. Still instantly killed people as soon as the beams spawned even if they were in the center of the room. On our kill, myself and another healer died in the center just as the beams appeared. Whenever this happens you aren’t even given a chance to look at the beams let alone dodge them.
Just need to get lucky and have it happen either closer to the end of the second room or have it take down 2+ healers instead of dps since healing the third room can be done with 1 healer. The 2+ dps are way more important. Could get really lucky and just not have it happen either.
We still killed it but it took getting lucky and having 2 healers die instead of dps. She took about 16-17 pulls due to the bug killing random people when we would’ve had her in 5-10. We even have multiple streams showcasing the bug but so does pretty much every other mythic guild.