It looks like it's saving the item while the screen is refreshing, but the item is simply gone. I have started using a name that doesn't appear anywhere in my vaults. Searching on the name after Saving produces no results. The item count in the navigation list does not increment from the attempted save. The item does not appear in my online account, nor any other machine logged into the account.
I am using MacOS 10.15.6 betas (19G46c currently)
1Password Version: 7.6-beta-3
Extension Version: N/A
OS Version: MacOS 10.15.6
Sync Type: iCloud