One thing I have noticed is when you are in poly circle mode with 20 or more voices and you are using a sound with a long attack and a long release, hitting the same note twice resets the envelopes and cuts off the release of the first note (like a mono synth). It works great if you play another note but not the same note twice in a row. I have tried everything to fix this one because it is very annoying when using poly circle mode.
A good example is preset 0059 Cosmology. Try hitting the same note twice (or a few times in a row) and the sound will be cut off abruptly.