This usually means that the rice at the bottom of the inner pot has started to burn. If this happens, turn off your Instant Pot but keep the lid on. Let it sit for 15 minutes, then check the consistency of the rice and the doneness of the chicken. If both are still undercooked, gently scrape the bottom of the inner pot with a wooden spatula, turn the Instant Pot back on and continue to cook in "Rice" mode.