After fighting the Herald and minions but before starting the section to put out fires. At point where NPC Charr should be interactable.
"Commander, I have something that might help with the flames"
Instance crashes out and returns to character select screen.
4 times with Ranger "Erithan"
1 time with Necromancer "Bindair Dundat"
Blocking progress. Can not play PoF expansion without finishing story.