I use the standalone local version and before you suggest it, let me say I am not interested in the cloud service.
I have 2 vaults both set to sync with a local folder. It has been working OK for a while. I recently discovered that after some upgrade (don't know exactly when) the sync options for both vaults got set to "None". I don't know what happened, but this is concerning, it makes me question the reliability of 1Password and the safety of my passwords if the app can change settings on me without clear warnings and confirmation on my part.
For others: if you rely on Folder sync, check your settings and make sure it's still enabled and works as expected.
1Password Version: 7.4.2
Extension Version: Not Provided
OS Version: 10.14.6
Sync Type: Folder