Hi liam !
Um ... I remeber to have the same behavior once and it turned out to be my m audio keystation controller . It worked fine with some cables only . At the end i had to be replaced for another controller :-/ .
BUT do you test the controller outside protools ? There is an utility to test midi hardwares in windows . It is called midiox , google it . Test differents lenght usb cables if possible .
Let me know
