Black Cathedral (Kulemak invitation) numerous bugs

I decided to try this content for the first time, didn't check it on forums first and encountered all kind of bugs with the boss:
1. Once we get to the last stage and if player clicks "Return the Finger" instead of take it we fight last stage of the boss and if player died once for boss - we have endless repetition of instance and fight, boss becomes untraceable (no boss HP, no statuses, I have to move to boss and see his state y eyes).
2. Most boss attacks are invisible: telegraphing of AOE is dark-greenish on dark-green floor, it looks like background light of the arena.
3. Arena is terribly small and boss spawns 1-shot beams sometimes directly over entire half of the arens (i.e. no way to survive this), sometimes beams cover both halfs. Maybe, it's better to force boss to beam only one half so we have to jump portal?
4. Sometimes player stuck on fissure in the middle fo the room and entire fight become broken (boss' orbs simply spand and fly over player, we can do nothing, boss not in the arena, because can't land). Orbs seems limited to 4 or 6, but they create terrible noise :)
5. No exit from arena, while boss is defeated or encounter is aborted by taking the item. The only way is to reset arena and teleport to last checkpoint.

P.S. Design of the boss and ring mechanics is awesome! Can't wait to see this fixed and repeat the fight again.