Apex cloth flickering and snapping in PiE

I have a simple skeletal mesh I’ve applied some cloth to. But for some reason when I preview the mesh/cloth or play in editor or the game, it flickers. Here’s a video.

has anyone else had this problem? I’m on 4.7.4.

I have some geometry that is behind the visible one that is weighted the same, so I’m not sure if that has an impact.

You can see in the below image (a still from the video) that the affected cloth vertex normals change somehow.