Midi tracks change when I change my midi instrument

I have a Yamaha MX88 and I’ll go to make a midi track in the project window and I’ll record, for example, a few chords with the concert grand piano setting. Then, I’ll go add another midi track for drums. So I change my Yamaha’s setting to drums/perc. Then when I go to record my 2nd track for drums, my 1st track for piano has changed to drums as well. I know I could make instrument tracks, but I’d like to use the sounds from my Yamaha. Does anyone know how to do this? Thank you!

You need to assign the sounds to their own “Parts” in the MX and switch the midi channel of Cubase tracks accordingly.