Quick update on this situation. I think this was a MODX issue. Looking at the MIDI data for sustain, the MODX was throwing random numbers other than 0 and 127. Hypothesis is that these random signals were causing the stuck notes.
Long story short, the MODX has a sustain menu I wasn’t aware of. (Utility/Sound/sustain). In that menu you can choose from half damper or full switched sustain pedals. Mine was set to half damper and I think that setting was tossing the bad MIDI messages.
I changed to a switched pedal setting and got nothing but 0s and 127s. I think that may have done the trick - more testing and some other tweaks as I practice for Friday’s show. Huge thanks to DHJ for the troubleshooting help!!