Same thing happened to a non worgen toon on my sisters account & this time she attempted to enable Carbonite Quest Module each time she completed one of the quests in her quest log.
Toon was 98 & had just gotten the quest to start Legion content when her entire game locked up.
At least for this toon the quest that had the Quest Module locked up was"
"Rite of the TalonPriests -Spires of Arak""
As soon as she completed that quest she enabled Carbonite Quest Module & has had no issues since.
