Calling CreateDefaultSubobject breaks entire project

So, I have a movement component:

UPROPERTY( VisibleAnywhere, Category = "Movement" )
UPawnMovementComponent*								MovementComponent;

In the constructor, I construct the object like this:

MovementComponent	= ObjectInitializer.CreateDefaultSubobject<UPawnMovementComponent>( this, TEXT( "MovementComponent" ) );

That last line results in the unreal editor using about 1.5gb of memory( usually it uses around 300mb ). IT also causes significant lag, though that could just be a result of low memory.

What’s wrong with this? Am I doing something wrong? I initialise other components like this with no problems at all.

Using the visual studio debugger, I found out it was crashing due to UPawnMovementComponent being marked as abstract. I changed this to a UFloatingPawnMovement and it works fine.

Obviously I did something wrong here. The crashes were happening while trying to display some error message, however.