A post on the Blizzard forum describes the issue: when entering or leaving a dungeon, the loading bar fills up completely, but then the screen looks as if the game were minimized — the only way out is to close the game via Alt+F4. No confirmation from the developers yet.

A player on the Blizzard forum described a bug that makes it impossible to properly enter or leave a dungeon. According to him, the loading bar fills up completely, after which the image looks as if the game were minimized — and the screen does not change. He tried waiting around ten minutes, but the load never finished; the only way to exit was through Alt+F4.

The thread currently consists of one post and one participant — meaning it's the only documented case on the platform. Blizzard has not provided any confirmation or a timeline for a fix.

In practice

• If the loading bar fills up while entering or leaving a dungeon but nothing happens afterwards, don't wait — close the game via Alt+F4 and log back in.
• Before your next dungeon run, save and keep a bag with reagents and consumables nearby: after restarting you'll have to walk up to the entrance again.
• If you've encountered this too, leave a message on the Blizzard forum: the more reproductions the team has, the faster they can track down the cause.