Hello and welcome to the forum.
It looks like you have a failed warning lamp. Every time you start your Fiesta, the car performs a system functionality test on all the warning lamp circuits of the vehicle. It is a federally mandated system test to ensure that the vehicle OBD and and other critical monitoring systems are working properly. You should go to your Ford service department ASAP. If the MIL is intermittent, you should take a picture of the screen to show the service writer when you get there.