KB3187: How to remove missing restore points from Veeam ...
https://www.veeam.com/kb318727.05.2020 · For versions prior to 11, the supported solution for removing missing restore points is to have the tenant run an active full backup or re-seed the cloud backup. Starting with Veeam Backup & Replication v11 (11.0.0.825), two PowerShell cmdlets were created, allowing a Service Provider to find and then forget those missing restore points for a specific tenant.