I'm missing something somewhere, or I have a software issue. Here's where I am:

There's a trumpet loaded in the solo track.

For the solo track, I'm able to select other instruments, like normal, the white arrow, or right click on the solo (or other) track, etc.

After selecting a new instrument, say accordion, generating the track, though the mixer (top right screen quadrant) displays the newly chosen instrument, the track still plays a trumpet. Regenerate, reboot BIAB, reboot CPU, return to factory settings (I reverted back after trying), no change. Close and open the song, trumpet.

I can right click the solo/mixer track and select erase track, erase midi, and the track displays an instrument I must have chosen way back; cello. But the track still plays trumpet.

Andy

BIAB 2017 Ultra
Windows 8 and 10
Scarlet 18i8
Reaper and Mixpad