I believe that the Korg Legacy M1 and Wavestation respond to poly aftertouch correctly. Although I am not near my DAW right now to verify this, Alchemy (may it rest in peace) does also.
It may be wise to verify that your controller sends poly aftertouch correctly. Years ago, when the Roland A80 MIDI controller was in production, we bought one. I quickly discovered that its poly aftertouch did not work. Trapping and analyzing its MIDI output on a sequencer (Cakewalk!) revealed that the poly aftertouch was being sent three octaves above the actual key pressed. And this was after the A80 had been in production for a few years! We were the first to notice this issue! Roland was very expeditious in producing a firmware fix, and the shop where we bought it installed the firmware fix quickly. (I don't know how such firmware fixes would be deployed in today's world of ecommerce.) The firmware upgrade was performed at Synthony Music in Phoenix, AZ ... a store which went out of business years ago and which we greatly miss.
My point is, the polyphonic aftertouch feature, and other similar specialized features, may not have been thoroughly design-verified by the controller manufacturer, since there are so few modules/VST's that support this feature. If you have issues with poly aftertouch, the problem may not lie in the module/VST.