Crimson Court, a piece of DLC for Darkest Dungeon, has a bug on the Switch version that makes it impossible to complete. The game's development studio has said they are working on a solution.
One of the features of Crimson Court is a location called The Courtyard. The Courtyard is a large dungeon that, unlike other dungeons, you can leave at any time and come back to later. The dungeon is designed to be left and returned to; it's too big for a party to complete in one go. Players are saying that when they leave the Courtyard, instead of starting from where they left off when they return, the dungeon starts over from the beginning. Another quirk of Crimson Court is that a disease that spreads among your party if they don't defeat bosses in the Courtyard. Combined with the current bug, Crimson Court is very difficult to complete.
Red Hook Games, the development studio behind Darkest Dungeon, has said they are working on a fix, and a representative from Red Hook told Kotaku that the fix has been submitted to Nintendo and is awaiting certification. Until that happens, your best bet is to avoid Crimson Court until the bug is fixed.