When running Veeam Agent for Microsoft Windows (VAW) 2.1 backups to a Veeam Backup and Replication (VBR) 9.5 repository, you can encounter the following behavior after upgrading VBR 9.5 from U2 to U3.
All VAW machines are moved to the
Unmanaged group. When trying to move these machine to another Protection Group (right-click > Move to) you receive the following message: