It depends on how one views "free tier," since if one doesn't pay when requested (whether from the end of a trial, just normal expiry, or if there's a separation event from the "free family for business") the vault remains yours and active, but goes read only.

I don't know what would lead you to believe there's any syncing restriction from 1Password, but if that is your experience it's almost certainly a bug, since to the very best of my knowledge 1Password doesn't engage in hostage-taking like that