It's not a bug, it's intentional. Once you reach a certain number of rooms in your temple, these things start happening. My temple didn't have these problems until I reached the Golem area. At that point, it randomly started happening that when I left, the temple would close on its own without me having to do everything, just because I went out to use medallions to expand rooms, to level up rooms, or to secure them with locks when they weren't locked when I entered.
I call it the moment when GGG decides it wants its players to abandon the game and go to another one, so they don't need staff in this one to fix things on the fly. Besides, they can't find any more problems to add to the ever-growing roadmap of pending fixes, which at this rate will be longer than the workload for a new league patch. It's sad, but many problems have been around for several leagues and remain unfixed. Even something as simple as the choices in acts should be modifiable, but they aren't. A fully equipped character might not be able to find a replacement for a choice that seems minor, but in the end, it could be the one that makes everything work for damage and survivability.
And let's not even talk about how boring it is to create secondary characters when you're not interested in playing the campaign again. Would it be so difficult for a character to advance to Ziggurat and only be forced to make certain choices with Alva from the campaign mode? This would allow players who create one or two characters to choose to create several to try different builds, and the change in act choices would allow for better adaptation of created characters to new builds. These are several details that would make many players spend money to expand the character limit to try even two characters whose only change is their ancestry, allowing them to explore more options.