So, there was a bit of red herring with the working environment as it, too, broke after we refreshed data in the register.
As it turns out, this is bug PF6-5346. Support is able to provide some code and a workaround (though I haven't implemented it yet.)
I am the client! XD
We only have one substantial maintenance window a year and we need some features in OFC SV3 which requires PV8. Plus, the .Net framework necessary for 8.1 is EOL in just a few months so it's 8.2 or nothing. The relatively short support windows from MS for the .Net frameworks may become a problem in the long run but that's a different topic.
Both of the 8.2 environments are clones of the same Prod environment and we specifically avoided any code/config changes to PLP. I can't fathom what would cause such an unusual display issue. I deleted the parameter and recreated it. I tried importing it from the environment where it works. The manner that the name/value datatable is built is wildly different for each parameter (the default parameter uses the API and a long function, our custom function runs a short bit of SQL) but ultimately they're both returning a valid datatable with the correct name (per their parameter settings) with valid column names and valid values.
There doesn't appear to be any valid way to explain the differences between the display of the two.
