Manual keys not playing correct notes

Hi All,
I apologise if this was addressed elsewhere, but I searched and couldn't find anything.
I recently got a new motherboard, processor and memory so that I could play the Melbourne Town Hall organ. I was setting up the manuals, pedals and pistons etc. and all was going well. However, when I went to play on the Great, I found that many of the keys were playing the incorrect notes and some were playing two or more and some were completely silent. I could see the corresponding incorrect keys operating on the console panel in HW. I believe that it is a MIDI problem with the key mapping from the great manual, but I don't know how to fix it. It is the same on all of the organs I have - the same keys play the same wrong notes etc.. The other three manuals and pedals play correctly.
I’ve updated all the drivers and chipset.
My system is:
ASUS TUF Gaming Z790-Plus WIFI D4 motherboard
Intel i5-13600K, 24MB Cache, LGA1700 processor
4x32GB Corsair Vengeance LPX DDR4 3600MHz RAM
Roland UM-ONE USB MIDI Interface
Focusrite Scarlett 2i4 external sound card
2 x ELO touchscreen monitors.
MCU bought from Classic in October 2015
I would appreciate any input you may have to help me fix this.
Thanks very much,
Jim

Under General settings | General preferences | Advanced preferences, please turn on logging MIDI messages, play some notes on your Great keyboard, and see what note numbers show up in Help | View activity log. Don't forget to turn logging off.

It sounds like your Great keyboard's MIDI encoding or cable has a problem, even though it's your PC that's new here.

Thanks very much - I'll try that!