This is a quite easy bug to workaround, but reporting it anyway. It doesn't show up very often.
I use a motorized single fader to control volume of tracks/channel strips. Several times, I've found myself trying to adjust volume without anything happening.
Workaround: Select a track with the mouse. This resets the MCU and everything should be fine (until it happens again).
System: Macbook Pro 16", 64GB RAM, macOS Catalina 10.15.7.
MCU: Presonus Faderport Classic Solo
Software Version: Logic Pro 10.6.2