[Quest] In the House of Light and Shadow

[ttromax]

WoW Freakz link: https://www.wow-freakz.com/quest_helper.php?quest=44448&name=in-the-house-of-light-and-shadow
Bug description: Clicking on Light's Heart in your order hall plays a cutscene, in which you're placed on top of some sort of invisible platform. During the cutscene I pressed some directional hotkey and ended up falling to my death. After clicking on the release prompt I'm just teleported back to dalaran. The cutscene won't play anymore from the second attempt onward, I'm just spawned in the nether on top of a platform (neither logging off or abandoning then retaking the quest will help with this).
Proof: https://imgur.com/1cTay70

[Power]

Delete the cache folder and try again.