RMAN crosscheck marks destaged backups as expired

Hi Team,

I'd like to know how best configure NBU and RMAN with destaging STU.

Basically the first backup is done to basic disk and the RMAN retention matches NBU retention (we have daily, weekly, monthy scripts)

To free disk space, this disk STU is configured for destaging, so NBU copies the backup to tapes, but it looks like RMAN is un-aware of this.

In fact, when I run a RMAN crosscheck, RMAN marks as expired the copeis that were on wisk and that now are on tape.

A possible but not viable workaroud could be to duplicate back the backup from tape to disk and rerun a crosscheck.

Are you aware of any other solutons ?

Is there a way to tell RMAN to restore from the copy to tape (after obviously making that a primary copy with NBU)

Thanks.

Francesco.