It's a common bug that people have been running into with this new version (some kind of event that triggers the meta-paranoia and just doesn't end). One way I've found to force a save is to clip into the backrooms. I crawl under the base (using that floor triangle with no collision by the front door to the left of the mailbox) and shoving myself into a corner and ragdolling until I clip somewhere and it sends me to the backrooms. I have stuff in the mailbox, so whenever the game saves it makes an alert noise, and I can hear it right before I'm transported. It's been working so far.