aahhhh onboard computers
A friend of mine had an Audi that displayed "Check coolant" and when he added Steering fluid, the signal disappeared
A year later, same thing although I don't remember what it was, but the computer told him that A was wrong, he fixed B and boum, problem solved.
I'm not sure why, he isn't either. Just a weird car...
So check everything
: and get the car to the dealership, they are used to it, and they might just reset the computer, and ask you to come back if it flashes again.