As the title says, the boss in this dungeon is still completely bugged.
1) If you deal too much damage, instead of skipping a phase, you have to deal with two phases at once.
2) If tremors occur, you still have a chance to glitch under the ground, how this has not been fixed yet is absolutely beyond me.
3) Certain mechanics are actively harder depending on which graphics settings you use. Example: When having to determine which beam is the biggest during the squid phase, playing on remastered makes it much clearer which one is the correct one, however, during the phase where glyphs appear on the tombstones and you have to stand on the corresponding tiles on the floor, using any non-remastered setting makes the phase a lot more coherent.

How the hell you can push out a whole dungeon and not manage to make the boss even work properly is beyond me and it's frankly an embarrassing feat from your developers. It strikes me even moreso as odd because during the NA vs EU Dungeon Event on Twitch, somebody from - I think it was - EU's team glitched under the ground. Having this happen at a semi-official event should have been motivation enough to fix this bug but here we are.

1 & 3, are designed rather well.  2 on the other hand it is like an entirely different team designed it and they were all masochists.  There is no reason to have that many phases to a dungeon boss.