Hi Rog,

maybe I can help?

It is this problem more often. Usually it was either the pitch bend wheel, or at even more of the Foot Switch socket behind Key. In the menu for the controller settings are at the Footswitch settings and the effect of GLIDE. When the SW1 and SW2 is turned on, it may be that the socket on the rear has a short circuit that is triggered by the shock to the housing while playing, and then the GLIDE effect permanently activated, and thus lower the keyboard one semitone but only the right hand. The auto accompaniment is not affected, ergo the whole sounds entirely obliquely, of course.
Adjusting for the o.g. Footswitch controller settings instead of the glide effect once a different effect, and test times, whether the pitch will drop still occurs. If not, it is certainly due to the rear jack. Or do you have a pedal connected to the jack, which is possibly defective. Then pull the plug out of the pedal once and test whether the drop is still pitch.

Press' Program Menus "

Then press "Control"

Then press "foot controller"

See if Footswitch 1 and 2 to "Glide" position.
Modify the effect of "glide" in another effect, eg Sustain and most, if the bug is still present.

I hope you can understand me.