Hi,
we have the same problem after updating to Veeam 11.
But I executed the veeam_backup_status.ps1 directly on the server and it takes only about 5 seconds, so I don’t think that this is the issue (at least in our case)
I found the following in the check_mk.log on the host: 2021-06-23 16:19:18.351 perf: In [1190] milliseconds process 'C:\ProgramData\checkmk\agent\plugins\veeam_backup_status.ps1' pid:[13976] SUCCEDED - generated [0] bytes of data in [0] blocks
Seems like the plugin does not run correctly when the agents executes it.