I'm a noob, so I apologize if this is obvious or old hat. (Or totally irrelevant!)

Every once in a blue moon, I'll hear an inappropriate dominant chord (usually the piano) played over a major chord. There is a checkbox somewhere that enables playing dominant chords for all majors. I also saw another setting to allow dominant chords just over the V major (which makes more sense to me). I'm not sure if those settings apply to chord subs or just to soloists playing over changes. (This also probably related closely to the "bluesy" check boxes, which I think applies just to soloists.) Could that be related to your issue and causing the "jazzed up" sound you're trying to avoid?