The 3rd Part of LFR Hellfire Citadel - “Destructor’s Rise” is currently bugged.
Upon entering you spawn in at Fel Lord. Kill Fel Lord and run up the stairs to go to Xhul’horac but his door is locked. The door where Khadgar usually stands is also locked. The only door that is open is where Socrethar is at, which should be locked. When you go to Socrethar and kill his 4 adds, Socrethar despawns and nothing happens. All doors remain locked. There is no way to get to or kill Xhul’horac or Mannoroth.