Why is deltaTime different in BP and C++?

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);