The buttons in the photos are the original EI buttons, not the current EI2 buttons. The original buttons were made from existing molds, which had a mold cavity identifier inside the plunger. With normal lighting, these should not be visible, but you can see that with intense lighting, they are. They are also a different material. A diffusive element placed inside the plunger would probably help with this kind of lighting. Grinding the top of the LED flat could also be of benefit.
The current EI2 buttons are from our own molds, have a diffusive surface (no identifiers) inside the plunger and are better for high intensity lighting. They also have a very different bezel and plunger design.