This sounds like dodgy information in the CD database, confusing the two CDs. This info is only what someone else put in, so maybe you can fix it. What I would do is something like:
- insert each CD, let it download the track details, then edit them: right-click on the album, choose "find album details", then hit "edit" in the box that appears. Fix the album and track details as appropriate, so that they're unique.