Ok here, I forgot you can just modify them inside of Unreal so I did that to test out that theory. Now here is a picture of how close it comes to intersection. That is the closest it comes now, so I can rule out intersection as being the issue too.
Here is a picture of the animation playing in simulate mode.
We have ruled out the following.
Skin Weight Transfer (The Jacket has no lower body bone weights painted on the sleeve and no arm weights painted on the lower body)
Cloth Settings (I have tried every combination and one by one set them to an extreme low and high value to see what results I get)
Physics body collision (I have deleted them completely off of the arms and redid the arms several times and even borrowed them from Paragon Assets)
Those above I think we can safely rule out…I’m not sure about UV’s I didn’t make them but from what I could tell those parts of the jacket weren’t close enough to anything to result in bleeding of weight maps.