Instant Pots have sensors that report when the temperature at the bottom of the pot is getting too hot. This feature is designed to prevent food from burning, but sometimes it is accidentally triggered when you sauté food in the pot before sealing. To avoid the "burn" notice, be sure to add the water right after you've sautéed the chicken in order to release any browned bits from the bottom of the pan. Don't be afraid to scrape up any stuck-on browned bits with a wooden spoon as well.