In case you were wondering, bug still exists 12/16/2022. This bug has some serious history, being around for at least 2 years. Blizzard should make an event for it at this point, commemorating the experience.
BTW just wanted to add, after dying to this boss multiple times, and 3 members leaving, we acquired 3 new members, all level 28. What we did was let those 3 level 28s go in by themselves, while the healer and tank (both 50+) stayed far far away.
The level 28s were able to take down the boss fairly easily by themselves.
It seems this boss is only a problem when there is such a disparity between levels in your party. The totem normalizes HP between party members. When you have high level characters, mixed in with low level characters, the HP distribution goes haywire.
So just friendly pro tip, you might want to either approach boss with lower levels or higher levels but not both as lower levels and higher levels together for this boss is what causes the problem.
Thanks Blizzard for keeping this bug alive. We hope to see you again next year.