Hello Jose Alberto,
Could you please send to us the configuration used for both tape drives you have in the bacula-sd configuration files?
It seems to me you have different devices configured with different mefia types in this case. Bacula "ties" volumes to devices through media types.
It would also help us to understand this behavior if you voild also send the output of a "list media" command.
If you have different media types configured for these tape drives, it will not be possible to use the tapes interchangebly unless we do some modifications regarding the media types in catalog.
Best regards,
Ana