When I started moving users to TeamsOnly, one of the first pilot users said that their contacts didn’t import from SFB. Some digging around turned up this blog post, that outlined how to roll back the Unified Contact Store (UCS) to SFB server to allow contacts to import. The challenge here though, is that the user’s account still listed SFB server as the contact store location.
Figuring it couldn’t hurt, I ran Invoke-CsUcsRollback for the user ID, and it forced the import on the next sign in. Given that UCS isn’t supported for TeamsOnly anyway, this has become part of the standard command set that I’ve run to move users from SFB to TeamsOnly.