Super easy to recreate:
Start with INIT, Press "Morph" button and select "edit b" change the filter routing to steiner parker for osc1, osc2, and noise. Now press the morph button again and turn the morph knob back and forth, You should see the LEDs for the filter routing fade back and forth. Now try repeatedly playing a note while turning the morph knob. The notes stutter and become delayed. I seems like the routine for changing the LED brightness has higher priority than the routine for responding to keyboard presses.
Curiously if you use the morphee or map something else to the morph control, the filter routing LEDs don't animate and the stutter doesn't happen. Only when fading the filter routing leds does the problem occur.