Hi all!
The essence of the bug is that when you enter a dungeon with a friend, you cannot start it. Solo only. But when a friend joins you and opens a menu to insert a key, it also opens for you and you can pull out the key. This bug also works when you initially logged in with a friend, in this case it is simply duplicated.
This happened after the last update.
Sorry about the noise in the background.
Video: https://youtu.be/fjUNQs_ZNMg
Time codes: 0:10 5:37 9:08