Hi Geoff,
I found the source for those spheres, they seem to be constraints created by the Physical Animation Component. Which explains why you are having trouble seeing it in game for you. We have it enabled for our in-game characters, the dummy character in the in physics asset editor has it as well.
The spheres are created here:
void UPhysicalAnimationComponent::UpdatePhysicsEngineImp()I tried adding a bit of epsilon for the position test but it would simply accumulate enough errors before waking up again.
My current working theory is that the Physical Animation Component is accumulating really small errors in the kinematic target it generates, causing the constraints to never fall asleep.