RME pitch and filter stepping

When I roll the pitch knob up and down an octave, it sounds smooth and natural like my real mini. When I turn the cutoff knob from around 7:00 to 3:00, it too sounds really close to my mini.
But I am noticing subtle stepping when i roll the pitch and the cutoff together at the same time.

One of my favorite original minimooog synth sounds is the sound of an airplane passing from left to right overhead. I raise and lower the pitch and the cutoff together to simulate the doppler effect.

So why is there stepping if its analog?

I just saw this thread…
http://www.moogmusic.com/forum/viewtopic.php?t=4524&highlight=stepping


but i am only using the voyager RME knobs…

What pitch knob do you mean?

osc 2 and 3 frequency knobs…

If this also happens without a MIDI In connection this will be fixed on the next version 3.4.