I honestly don't know what to do with this little quirk Karma has. If she is corrected/nervous/bored/whatever she does her smile.
I have been working with her halting on the lunge line. Her idea of a halt is come to me for a treat. My idea of a halt is stopping wherever she is. I have been making her back away from me. Her solution to this is smile at me.
I took her for a short pony around the park. She was starting to get tired at the end and her solution was to drag on the lead rope and smile.
If she is standing and gets bored she will start smiling. I have this fear that is growing deeper and deeper that I am going to be doing a free walk and she is going to poke her nose out, twist the neck and smile for judge.