Thin walls showing wrong side in front in Safari

I have an app that starts with the camera zoomed out, then if the user selects an object it zooms in. In Chrome it works fine, but in Safari (desktop and mobile), the ribs and structures of the interior of the model show through. I’m attaching a zoomed out view and zoomed in view of one object (in the app the object opens up so you can see the ribs, etc). Is there a way to fix this?

‘Backface culling’ doesn’t fix it, as the ribs and pillars are not two dimensional. They are cubes and cylinders inside the object.