Sooooo, after four months of no solutions from support or community, I stumbled upon a solution. It's an obscure setting and I'm astounded that no one in the community or in tech support after many months had an inkling of this.
In preferences, under advanced, there is a setting under Automation called "Reduction Setting". It is by default set to 50 (0-100). I looked this up in the manual and it says that it also affects MPE data. So, I switched it off, or to "0". MPE pitch playback is working now. I'm not sure how this may affect my processor load, but it works.
Four months of no accurate MPE pitch playback and absolutely NO ONE at PreSonus support or community had a clue.