I’m using Cubase 10.5.20 on Windows 10. I load an instrument channel with Prologue, select the sound “clean recorder” (under woodwinds) and play a note. Then apply pressure to the note, I hear the effects come in, when I press the note hard it just stops! After that the patch stops playing - some other patches do still play, some don’t. I haven’t found another patch that causes the problem. The keyboard I am using is an Ensoniq MR76.
I’ve done some tests where I recorded a short phrase with a sustained note, I looped it and drew in the aftertouch. If I draw “hills” with rounded tops it works OK, but if I flatten the peaks at maximum level then it stops - but not at the peak, it seems to be a cumulative effect. Of course if you are actually playing then you will often press down and hold the maximum level.