I am using CW 2019 with DBcodes. Every time I make a change to the base catalog and accept the update from base to project catalog when going back to the prj file I lose some dbcode selection for certain items. When I repick the dbcodes and save the prj all is well until update from base catalog again.

I reviewed table links, but it shows no mismatches or updates pertaining to the dbcode table. Is there some way to diagnose what is happening between my prj and cat files?

This was a spec I upgraded from CW 2014.

Thanks for any advice

I also notice I have duplicates for every entry in the Component Types table.

Ufh, from 2014 to 2019... i suggest that you rebuild your catalogue. I also using DBCodes for one project and I am keep finding strange things to happening with that codes. I find out that tables are not linked correctly even it says that it is linked. Try to export your database from model, and check LIB_FILE column for some miss-mach catalogue link.
Faster way, in project catalogue press the preview button next to the Data Table in your edit component window. You will see which table is linked in Base Catalog Data Window. Sometimes is wrong table.
However, try to build new catalogue maybe just for one piping spec. and see if it working ok. Good Luck