Meadowlion

This is really odd but occasionally when activating the right turn signal it will show as flashers on the dash this happens very rarely and is corrected by just moving it back to the resting position and then signaling again. I can never tell if its actually activating both signals or if its just showing on the dash incorrectly. I have checked all my bulbs and they are in working order. What should I check next? My truck is a GMC Sierra 2004 4.3L Automatic 2WD.