If the song loaded into BiaB has the Thru part set to some guitar patch then that will be what gets loaded with that song.

There can also be a situation where that is only one song, but the Thru part does not have another Patch saved with it for the succeeding songs, so then it stays there.

If you find that particular songfile, you can change it to Piano using the dropdown slot and Save the song again so it won't do that. Or use Save Sang with Patches and Harmony to save it and check to see what is really selected on each Track first.

There are a few Global ways to always force the same Patch on one track such as the thru track as well.

--Mac