Two things: use iframes or party protection skills OR do a mechanic.
If you run out of a set time, a boss will enrage and cause a wipe, and this was the case for years.
Tons of things are bugged and they don't care.
For example:
- RT last boss, when jumping during mechanic, shockwaves spawn in wrong places, or players get CCed RANDOMLY during a fight
- EL is an old dungeon, yet the combat is STILL SHARED, means if one person is in combat, EVERYONE will be for the whole duration (unless someone's out of combat at that time, which often is NOT the case), and I'm pretty sure that everyone experienced WALKING for 30-60 seconds while being unable to run