One of my teams is having a weird issue and we’d be grateful for anyone who can give us some advice.
Their intake has two motors that are coupled together on a y-cable. At certain times (without user input) one of the motors starts spinning without the other. That same motor will also turn when one of the drive motor starts up. We’ve changed the cortex, y-cable, and motor controller and the issue still happens periodically.
There are 2 motors on a y cable and only one starts spinning? Are you sure that there isn’t some odd wiring? Do both motors work normally otherwise?
Could you post you’d code using the CODE </> tags to check that it’s not something in your code.
Ghost motor. 
Do the motors ever move at the same power at the same time?
The only thing that comes to mind is to make sure the polarity is right on both motors (line up the colors, not the metal showing sides).
Also, have you double checked that both motors work?
The only other thing I can think of is a bare wire contacting another bare wire in such a way that the electricity intended for one motor is transferred to the y-cabled “ghost motor.” That’s really unlikely, but it’s worth checking.