Boss phasing is broken in several different areas.

There's a major bug with bosses that have invulnerability phases (doryani, crow bell, etc.). If you damage them faster than their AI can keep up with, they will become invulnerable forever and simply never phase.

I think something in the boss monster behavior code is creating a deadlock, where it has conflicting triggers. IE:
- If boss monster would take damage to reduce it to <5% HP, become invulnerable at 5% HP instead
- If boss monster is in bell area AND takes damage below x hp, start next phase

If that is the case, then the monster is now in a deadlock, he can't take any damage because he was already invulnerable before he got to the bell area, and he won't phase without taking damage. This is speculation, but I'd hazard a guess it's something along those lines.

GGG, there needs to be an override to forcibly stop all other actions the boss is taking and prioritize completing its phasing behavior over every other action, otherwise you end up like me - losing all the content and rewards on a map and having to wait 15 minutes for the instance to expire so you dont lose exp. All because of bad code, not player error.

Video of bug https://drive.google.com/file/d/1FoZWdNGQrmWW9Jo3xkUmSRiHqju0tHsL/view?usp=sharing