Unfortunately, Apple both in both MacOS and iOS has only limited support for WebGL. It will only load max 8 textures so parts of the scene might not show up.
Apple support might change in the future but for now, we will have to think of workarounds. Unfortunately, it hampers getting visually appealing 3D content to Apple users.
It is nothing Verge3D can do about. Apple might change its mind. We will just have to be patient…