When moves over the Actor set after PrePhysics( e.g. DuringPhysics ), the bone with the physics enabled will stretch.
Instead of directly using PhysicsAsset, using RigidBody nodes does not cause this issue (even if it is set to WorldSpace).Also, this issue does not occur if you disable tick of the floor.
result : The bone is extended (delayed?)
There's no existing public thread on this issue, so head over toAnswerHub just mention UE-70064 in the post.