Hi Benjamin,
Yes this is intentional. I am a little surprised that the function below this isn’t putting the whole island to sleep, but that could be due to the jittering you mention.
I’d suggest using a system approach for this (ie call through the ‘owner’ class) - there are functions such as USkeletalMeshComponent::IsAnyRigidBodyAwake and USkeletalMeshComponent::PutAllRigidBodiesToSleep which should help you.
All the best
Geoff Stacey
Developer Relations