When the Shiritaki Temple Instance Quest is completed and it's time to fight the Plague Oni, occasionally players get stuck behind a loading screen which will not disappear, even if the wizard teleports to their house or to the Jade Palace. This forces players to REPEAT the dungeon if they are soloing, which is very annoying.
I've never gotten stuck there - but I do know that loading screen takes an insanely long time to load. There are other loading screens I've seen like this, but I can't think of one off the top of my head - this is the one that I remember (because I'm a constant re-roller, so I've done Plague Oni enough to write a book about him...), which takes a really, really long time to load.