Symbol classifications getting discarded in DFA PkgToPkg Spacing symbol browser - OrCad X

I’m running into a problem where symbol classifications in the OrCAD PCB Designer get discarded as I am trying to assign package-to-package spacing rules. Software version is OrCAD X 23.1, OrCAD PCB Designer Professional, 23.1-2023 S002 [2/5/2024] Windows SPB 64-bit Edition.

In the constraint manager, under Manufacturing->Design for Assembly->PkgToPkg Spacing I created a DFA spreadsheet, created new symbol classifications and assigned parts to the appropriate classifications. The spreadsheet (table with all of the spacing values for the different class combinations) looked as expected and I was able to complete initial placement using these spacings (tool showed DRC error flags when parts were too close).

At some point after this (as I was routing and adjusting placement), I noticed that I was no longer getting DRC errors when parts were too close. I opened the DFA spreadsheet again and the spreadsheet had not changed but the symbol classifications I created had vanished and many parts were no longer classified. I figured there had been some glitch so I just created the classifications again and assigned parts to them. After I clicked OK on the DFA Symbol Browser window and then opened the window again, the same classifications I added were no longer there. This is now a permanent problem with this design.

What could be causing the DFA Symbol Browser to be rejecting all of my new symbol classifications, after initially allowing me to create them and use them for placement? Why would it still show all of my original classifications in the spreadsheet?

Thanks for any suggestions  -Jason