EDIT: The issue seems to have been fixed after 1.19.9.0 update on 2021-09-17. Either that or the fact that the KB update was reinstalled by Windows update. 
For me this was caused by KB5005565 that released on 2021-09-14.
I should add that I am running Steam version of MSFS 2020.
New topic with this issue can be found here: Press any button to start loop after installing KB5005565