For the benefit of anyone else following this thread, we were also communicating with this customer directly via support@plugable.com and in this case the solution was to reset the docking station by using these steps:
“To do so, please disconnect both the power and the USB cables from the back of the dock and keep them disconnected for at least 30 seconds. Reconnect the power cable first and then wait at least 10 seconds. Then reconnect the USB cable to to your laptop see if the USB devices connected to the dock’s USB ports are now being detected correctly.”