sorry for my bad english (usually I write and speak german

I updated Veeam on version 9.5 and later on 9.5U1. Since the upgrade on 9.5 I get warnings and errors in tape jobs.
I get the warning: "Failed to eject tapes" -> Ok this is fixed with registry key
Furthermore I get the error: "Library IBM 3573-TL E.20 does not contain any enabled tape drives". It does not always happen, if it happens than always on different tape jobs and it usually happens if the previous job reports:"Failed to eject some tapes".
I noticed that it often happens when serveral jobs wait parallel to a tape drive. This happen because the scheduler is configured that the tapejobs start after the diskjobs. So I tested and change the scheduling configuration, that the tape jobs start at a specific time, always with a little timegap between the jobs. With this configuration the nightly tape jobs run well but this could also have been random. This configuration is not optimal so i went back to my standard scheduling configuration. The error occurred again.
The other configuaration: The Library (IBM TS-3100, LTO-5 drive) is connect via Fibre Channel to a physical server. According to support the hardwaremanager, the registry and the veeam databases look great.
Anyone with the same problem or any solution?
Greetings FabianF