USkeletalMeshComponent::USkeletalMeshComponent() caches off the teleport values for later use and then ignores the exposed values entirely. This should not be the case. We either need to detect changes or remove the exposed values and add a get/set pair that recalculates on set.
1) Add clothing actor to level
2) After BeginPlay, change a teleport threshold
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-40285 in the post.