The registry hack worked, the files are no longer going off line.
[HKEY_LOCAL_MACHINE\SOFTWARE\Veeam\Veeam Backup and Replication]
The support engineer said that there is no KB article regarding this registry key.
Here's what he said: "Regarding the details of the change. The registry key changes the way how heartbeat process is performed. With key set, it doesn't create temporary file on repository to verify that it's writable. You can work with this key set, no issues were reported on using this key. There is no KB on this. "
Does anyone else have any information regarding this key?
Was there some change between the heartbeat process between Veeam B&R 8.0 and 9.x?