Your output is from describing a successful backup, right?
For your unrestorable backups, did you try running describe with --deep ? I found recently that if you run describe before the backup is complete, it caches the metadata (including that is is incomplete and unrestorable) and still continues to report that if you run describe after the backup completes: Backups not "restorable" after 6.3 upgrade - #2 by amanda