Backup Exec 2012 with 16 tape robotic library.
I backup to disk and then duplicate to tape for weekly, monthly, and yearly. Duplicating to weekly (the default Keep Data for 4 Weeks) works fine. The Monthly and Yearly jobs will write to tapes that are set to scratch, but once the tape is ejected from the drive, it is set to not appendable. If enough jobs are queued up it will keep writing to tape, but as soon as the tape is ejected it goes to not appendable. The tape is not full, has the correct overwrite protection etc.
This is only for the monthly and yearly jobs that I had already created and are being used by all my jobs...I can create a new Media set with the exact same settings as the current Monthly and Yearly and they work fine. Anyone seen anything like this? I'd hate to have to go through all my jobs and edit/re-create using "New" monthly and yearly media sets.