Clean-up "old" data

Just to explain what is going on, Lightroom Classic carries out a Catalog conversion whenever a new version requires that and the results are saved as a new file. By default, the version number is appended suitably. But the old Catalog remains on disk. Until you change something, the contents of the two Catalog start out the same and the imported images in both cases refer to the same single set of external files and folders on disk. .

The v13 Catalog will open directly in v13 software. The v12 Catalog will still open directly in v12 software if that is still installed. If you open the v12 Catalog into the v13 software it will prompt for conversion into a new v13 Catalog. You already have got one of those. So I suggest taking the non-v13 Catalog entries out of the computer once you have reviewed the v13 Catalog that you are currently using, and satisfied yourself that the contents are OK. It seems that Catalog conversion may have happened on 12 September. Probably if anything had gone wrong in the conversion to v13, you would hav discovered it by now?