Mac Codebook Locking when Switching to a Specific Category

I use Codebook 3.0.2 (326) on a Mac. It seems to be OK, but there is an issue when I attempt to switch to a specific category that causes Codebook to stop responding. I can still see information, but all the entries are from the previous category I was looking at and I cannot access any of them. The only way into this category is to quit Codebook and start it again in that category, when I can access it normally. I am not sure if it is an issue with this version of Codebook or the database.

I have reinstalled the app via the App Store (this is how I originally installed it as STRIP, and how I updated it), overwritten the database from the Google Drive backup, which is the same database that is working correctly on my iPhone and restarted the Mac, plus I have deleted all the preferences I could find (though they were all “STRIP” preferences rather than “Codebook” preferences).

Any ideas how to overcome this? I have thought of exporting all the records and re-importing them, but haven’t tried this yet. I cannot see any updates on the App Store and am not sure if anyone else has had this issue (a search of this group didn’t highlight anything that may be appropriate).