The CADC-0011 entry is not a dupe, it's the official release.
The other one is promo. (haven't changed that yet)
Previous entries of chara-ani "bonus discs" have been handled with a separate entry and i still don't know if that was the right choice.
Here's the recap. if anyone want to check them:
The Legend of Heroes Sora no Kiseki Drama CD ~Decision To Leave~ / ~Bonds Tied Together~
came with
The Legend of Heroes Sora no Kiseki Theme Song Album
The Legend of Heroes Sora no Kiseki the 3rd Drama CD ~Tama no Kokuin~ / The Legend of Heroes Sora no Kiseki Drama CD - Joshua Story ~Sealed Memory~
came with
Legend of Heroes Sora no Kiseki Limited Edition Privilege Theme Song Album
If we'r following the previous entries, the bonus disc with CADC-0011 should be added separately.