The chrome inside mine is starting to turn black, almost looks like mold, but it's the chrome that's corroding.
Luckily mine are tinted so you can't really tell, but it's starting to show up around the reverse bulb where I don't have tint.
It's only been about a year since I installed them. Functionally they are perfect.
DEI 2-way Alarm & Start / DDM Ballasts + 6000k 55w HIDs in Eagle Eyes Projectors / 6000k 55w HID Fogs / All INT+EXT LEDs / K&N Air Filter / 35%/20% Tint / Maxxsonics MX-1 + 2500W Stereo