Then you may not be aware of how it happens. Everytime they are not in the boss room during a boss fight or the tank skips mandatory bosses, it happens. Very noticiable during turbulant timeways. Maybe someday I’ll make a list with all the dungeons that have this potential problem in it.
Twink tanks are the biggest abusers here as they at lvl 10 or 11 are able to kill so fast and get so far ahead that it causes players to miss boss fights and end up with wasted time by having to repeat extra dungeons to get to 5 for the weekly or get to 4 for the vault.