> It was in reference to the previous paragraph of list results.

I still don't get it. Can you perform the following and paste the results?

1) Allocate channel for maintenance...
2) Crosscheck backup (or the specific piece)
3) list backup piece=...

I expect step 2 to change the status on that piece from "unavailable" to "expired".

4) delete expired backup ...

Error message.

It's quite possible that I may not have a solution at the end of this exercise. I'm only trying to help. In the interim - "help me help you".