Unknownreported this bug
If a player leaves the server, the dungeon will not be cleared.
I also noticed that if a player leaves the server and comes back, it's as if they forget that it's their dungeon and some features stop working.
KickOfflinePlayers: true
# How long to wait in seconds after a disconnect before kicking the player from the dungeon.
KickOfflinePlayersDelay: 10
# How long in ticks to wait before cleaning up a dungeon when all players have left it. 0 will clean up the dungeon instantly.
CleanupDelay: 60