Auto-Fixed after 8 days.
Hey guys,
I had the same issue with my Q50 2014.
At May 5 2019 i got a flat tire warning(front left tire) like all here. On same day we found a way to repair tire and i ordered new run-flats and yet waiting them to arrive. So i decided to wait till i get them.
Yesterday at May 13 2019 it was auto-fixed.
I can't say it' because of 8 days ,or miles (approximately 70-80 miles),but in any case it was auto-fixed.
Also one of our guys who has FX35 told met that it will be auto-fixed after multiple engine start-stop(this also can be as during 8 days for sure i started the engine at least 16-20 times

). Theoretically this is also possible.
But don't waist your money ,just be a patient and flat tire warning will be auto-fixed after some time (in my case 8 days ,about 70-80 miles , and approximately 16-20 engine starts).