I am having an issue with RealTrack chords, one of the bluegrass sets in this instance. I have several songs I use as backing for practice, and each time I play the song I get some different chord variations; (Biab) plays an off chord for a measure (not sure what it is playing, but definitely not the basic chord intended). This only happens some of the time and the altered chord appear in different places each time I load the song.

Under song settings I have everything unchecked other than generate a 2 bar ending. That turns off embellishment chords and other substitutions, so what other setting am I missing that is throwing in these odd chords? Is it part of the style perhaps?