Lift and coast starting from lap 13 for Leclerc was neither for engine nor for brakes, but for tyre temperatures. In lap 11 Bryan said to Leclerc that he should take care of the tyres and a lap after he instructed Leclerc to lift and coast into the braking zones. After the sprint race Leclerc said to Bryan that they pushed too much in the beginning.
Now, some might ask why all of a sudden Ferrari had tyre management issues and the simple answer to that was the biggest weakness of the car which still remained despite the very successfull latest upgrade and that's the instability in high speed direction changes like in S1 in Interlagos.
Ferrari will make changes to the suspension setup to mitigate this issue for the main race. Though, seems like the weather solved this problem anyway for today.