I am having the same issue on the Switch version today after the update and also it keeps doing an autosave literally every 30 seconds.
It's happening ion the Nintendo Switch version too if that's any help to who ever is looking into this, I click the button, it goes to the loading screen then I get the "The game crashed due to an unexpected error" message.
Can't get into Realms either, same issue with the Marketplace.
Worked fine before the update.