Creating a new catalog and importing previously processed images: Keyword field issues

I was helping a coworker with his files and created new catalogs just for his 2022 and 2023 photos, respectively; he had a few years in the same catalog and for how we operate, that's not an ideal setup. After importing the photos from 2022 into its new catalog, none of the keywords were showing up; star ratings and edits did show up though, as well as Caption, Title and Event fields. No Keywords though.

All metadata was saved prior to creating the new catalog, and I kept the 2022 photos in question in the old catalog in case. If I opened up the files in Bridge, the Keywords are there. I tested one folder and removed the photos from the catalog and synced to add them back, and the keywords appeared again. So I removed all the photos from the catalog and synched and now everything is good for 2022 files.

However, for his 2023 photos which were added to their own 2023 catalog (and he removed them from the original catalog), the keywords disappeared from the XMP sidecars, even though the metadata was saved prior to closing out the old album. The Description, Title and Event fields are there though, and in general, this information is added after Keywords in our workflows, so the metadata was saved into sidecar files properly and I wasn't looking at an old version of the metadata.

So it seems in one case LR just didn't show Keywords that are there, and in another it seemed to clear out the Keyword field, and only that field.