I manage several tenants, and have OneDrive B2B sync working b/t 'Fabrikam' and 'Contoso'. The Contoso user is a guest within 'Fabrikam' and is syncing a document library within 'Fabrikam'. The Contoso user is using KMF.
Everything is working properly EXCEPT the following scenario, which seems to be easily reproducible:
'Contoso' user creates content on his/her desktop (say a Word Document or PDF). Then, this user 'drags and drops' the file (considered a 'move' and/or 'cut + paste' operation) to the synced document library within 'Fabrikam' via File Explorer. The OneDrive sync client never seems to completely processes this change: Visually, the document is removed from the desktop, and can be seen with the blue 'sync pending' icon in the synced document library within File Explorer. This status never changes. The users within 'Fabrikam' never see the document appear in File Explorer and/or Sharepoint web view.
The operation described above works properly, instead, if the user does a copy + paste operation.
The reverse is also true: If the 'Contoso' user does a 'move' and/or 'cut + paste' operation for a file from the synced document library in 'Fabrikam' to his/her desktop, the file visually appears on the desktop with the blue 'sync pending' icon, which never changes (expected to appear as green check mark, 'available on this device' status). The users within 'Fabrikam' never see the file disappear .
Sync Clients tested: