If there’s a signal present at the input, turning down the Drive knob quickly can momentarily cause clipping. There’s a long technical explanation of why this happens having to do with the number of interactive parameters that have to be simultaneously adjusted by the software when you make quick changes, but we’re not going to bore you with that. What it all boils down to is that the clipping only occurs while the knob is moving quickly and towards minimum so don’t worry about it (or just slow down).