I haven’t heard anything yet in regard to this being fixed. I would assume the easiest way to check is try to find a group to run it on heroic since it’s bugged on all difficulties from what I can tell. As soon as I find out that its been resolved I’ll edit the title to reflect as such.
edit I did find this post which is fairly recent that sounds like they were able to defeat the last boss, but did not receive any loot. So the mechanics may be fixed but loot may be an issue now?