As you probably know, car manufacturers don't make the components that make up the car, they just put them all together. For most components vw will have several suppliers and although they will all be working to the same vw spec, there's bound to be some tiny differences, even if they look identical.
It could be, a certain light unit manufacturer is using a slightly different method or material which behaves differently in certain conditions? If there is a way of seeing who has made a misty light unit from the serial number or something, maybe check it against a light unit you know that doesn't mist up and see if it's a different supplier?
It could be, a certain light unit manufacturer is using a slightly different method or material which behaves differently in certain conditions? If there is a way of seeing who has made a misty light unit from the serial number or something, maybe check it against a light unit you know that doesn't mist up and see if it's a different supplier?