During the formation lap, marshals wave green flags and yellow flags flash on the steering wheel.
In real F1, there shouldn't be any flags. This can be seen in the attached video. It also shows what drivers do during the formation lap and the procedures that apply.
In the F1 game, these flags should be disabled. It would also be worthwhile to add mapping for brake balance changes [+10%] and [default value].
https://www.youtube.com/watch?v=Hx72Yo5WtVs
