Reproducible every time: adding a new track disconnects the FaderPort Classic forcing the user to go back into Studio Setup and add the device again from scratch. Please fix! 
I have sold my Cubase 10 because of that. Good luck!
BTW, this is my original post:
+10000000000000
I am starting to wonder if this is an intentional bug so people will tire and buy the Steinberg CC121 controller instead? 