I guess the solution is to do as suggested:
Changing this in LevelTick.cpp
// Clamp time between 2000 fps and 2.5 fps.
DeltaSeconds = FMath::Clamp(DeltaSeconds,0.0005f,0.40f);
To
// Clamp time between 2000 fps and 30 fps.
DeltaSeconds = FMath::Clamp(DeltaSeconds,0.0005f,1/30.0f);