DDJ-FLX10 USB INPUTS ADVICE NEEDED

We have a customer that recently purchased a FLX10 and is connecting two separate PC's to the USB A and USB B inputs. Then he is switching back and forth between the two inputs on the fly, on the same channel. 

When switching from A to B, sometimes A will still play, and vice-versa.

We told him that this is probably not the intended use and he shouldn't do that. Anyway. Sounds like normal operation for an abnormal situation.