When I referred to the shine, I wasn't referring to the distortion of the background, but to the white lines on the side of the glass. Their position should be independent of the boxes' rotation; the glass boxes aren't the light source, after all.

But since you brought up the background distortion: the tiles don't really indicate that the glass on the side is broken, just the top of the box. Adding an outline where the glass is broken (and distorted background behind the areas that still have glass, since that's what you'd expect) would be a good way to convey that. I also just realized that the background that's being distorted is different from the "normal" background in the first place (it's that tile in the bottom right).