I have been dealing with an issue where a Veeam backup copy job is not running periodic compaction of the full backup file. In my case I need the compaction to run in order for the full backup file to be re-aligned to the ReFS block size to allow fast clones to work. The fix is as follows:
1. Create the following registry key:
Registry path: HKEY_LOCAL_MACHINE\SOFTWARE\Veeam\Veeam Backup and Replication\
Name: BackupCopyJobForceCompact
Type: REG_DWORD (0 False, 1 True)
Default value: 0 (disabled)