I checked the c.haos code quickly. I think it caused by the function "bool FInitBodiesHelperBase::CreateShapesAndActors()". In this function, the CreateActor_AssumesLocked function will ignore the scale information, and the CreateShapes_AssumesLocked function will use the scale information by GetFinalScaled. And the negative scale will make the shape mirrored.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-142739 in the post.