On iPhone 5 (possible all iPhones?) using point lights with Non-baked affect AND Shadows enabled will cause all the models to disappear. If either the Non-baked or Shadows setting is disabled, the models in the scene will appear properly again.
Notes:
I’ve tested this in both Safari and Chrome; the bug exists on both.
It doesn’t seem to matter if other lights exist in the scene; a single point light with those settings enabled will break the scene.
Here is an example (the starter model viewer project–the only change is that I changed the light from a directional light to a point light).
Such behaviour can happen when some shaders fail to compile, leading to object to become invisible. We will check project on iOS some devices to see if we can replicate the issue.