light piped eyes is nothing new, we first had it in Transformers Generation 2. In some cases it seems that Hasbro sometimes changes their mind at the last minute when it comes to 'cancelling' light piping, so they'll replace what would be a translucent piece with a solid piece. We had quite a few Transformers with this in 1996-97 e.g. Waspinator, Machine Wars Megatron etc. What's occured more recently is, as kup described, actual translucent plastic put in that does light pipe, but then that plastic is painted over. My guess is that it's a last second decision to 'cancel' the light pipe.
I find it to be pretty annoying as the problem you have is light "weeping" out of the corners of the eyes. (T_T)