The PositionBaryCoordsAndDist, NormalBaryCoordsAndDist, and TangentBaryCoordsAndDist data that all contain the vertex distance information to the simulated triangle in the cloth shader doesn't scale with the character.
The data is static, created at authoring time, and doesn't contain the component's scale. Therefore the distance information would need to be scaled either in the shader, or during the copy to the shader buffers.
Actual Result: Cloth will bunch in on itself, vertices float in all different directions, etc.
Expected Result: Cloth simulation should be consistent regardless of scale.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-173715 in the post.