Peterd, I think what saves you is that the lamp itself is much larger than the actual light source. So most of the lens area are at a distance from the bulb, not lightened with full intensity and appearing red as it should. From your photo, if you look directly at the light source behind the lens, it appears - permit me to say so - pink. Not a problem in your case, but could be if you fit a white LED in a rear driving/stop light. I do not know if the thread starter has done exactly that, but from his photos it looks like it, although I could be mistaken. At least, that it how it can appear with a bright white LED behind a red lens.
