Onyxia bug: No phase 3 - WoW HC - Nek'rosh

During our Onyxia encounter she decided to just stay in the air and never really started phase 3.
Not much to do for a healer until phase 3, so I'm pretty much chilling the whole fight and not taking it very seriously.
Guild: Infamous
Server: Nek'Rosh EU
Mode: WoW Classic HC