Why doesn't scaling an actor with child actors work

I have a blueprint which contains 4 Child Actors for components. When I spawn this actor, I set its world scale:

NewBuilding->SetActorScale3D(ScalarVector);

Where NewBuilding is the just spawned AActor*

On my existing actors this works fine. However, I have just made a composite actor blueprint using, as I said, child actors for components. The scale is correctly set if you look in the details panel in the editor. However, the object is not scaled accordingly.

Weirder still, if you change these these numbers (say set the scale X to 1.0 and then back to 10) it correctly scales (in all three axis!)

It also still happens if you use SetActorRelativeScale3D.

OK the problem seem to be caused by the fact some of the actors contained a static mesh component with its mobility set to Static. I don’t know why this wasn’t causing the single component BPs to fail though… I’ll post this as an answer unless someone can come up with something more informative.

I’m having the same issue (https://answers.unrealengine.com/questions/135505/setactorscale3d-c-not-working.html).