Loud notes from MOX to Cubase AI

This is driving me mad. I have Cubase AI hooked up via USB to a Yamaha MOX. Suddenly every time I open Cubase I get a loud A above middle C from the MOX, and the same when I click record, and the keys A, Bb and B are ten times as loud as any other. This regardless of click being on or off or local on or off on the MOX.

This appears to be a glitch as someone has posted similar on Motifator. Anyway, I uninstalled the Remote Tools and reinstalled and although I haven’t tested all circumstances, all seems to be well again. Still interested in any comments on the cause, though.