RM 8.2.0 - DB gets wiped

Hello, I am seeing an unusual issue on one of three Macs that I use, an M1 Macbook Pro with 8.2.0. What happens is that I create DB, import a gedcom, do some work on the DB, maybe synch with Ancestry, and at some point I do an operation such as Automerge, and all the people in the DB disappear. There is no error or warning, no crash.

I’ve never seen that happen. Where is the database located? Is it being stored in the cloud like with Dropbox? If you close RM and reopen the database do they appear again?