Wanted to share a weird occurrence on my SX-900.
While trying out some 3rd party styles and registrations, I then loaded a few factory styles, (or any of my saved styles), that had 3 right hand voices in OTS, but only R3 would play in a solo and not in combination with R1 and R2. If I turned off R3, R1 and R2 would play solo or in combination, but not with R3. The mixer showed R1, R2, and R3 all to be on. Somehow R3 got messed up in a previous 3rd party style or registration OTS load.
So...
I then loaded one of my own saved registrations, that had three right hand voices, they all played normally, and any styles loaded after played normally with all three right hand voices working again.
Not sure how that happened, but that's why it's good to have saved registrations to bring things back to normal