This issue is caused by the Cortex XDR agent. This agent is crashing the sqlserver.exe process on the Veeam Agent machine. The Veeam Agent backup job fails as the Veeam Agent configuration database is hosted on the SQL LocalDB instance.
Restart of the Veeam Agent for Microsoft Windows service resolves the issue temporarily as it restarts sqlserver.exe due to dependencies of the service.
C:\Windows\System32\config\systemprofile\AppData\Local\Microsoft\Microsoft SQL Server Local DB\Instances\VeeamEndPoint\error.log shows: