my '07 X5 4.8i is doing the same thing, both sides. It was only noticed when I went in for inspection this week. My OEM warranty expired late July, I'm sure there was moisture in the lenses at that time, just no one noticed. Got quoted $600 for both lights replaced by my dealer- which is crazy. They refer to it as a wear and tear item (gaskets). The car has 39,000 miles on it and is always garaged...

I appealed to BMW NA, but fell upon deaf ears. I've lost a lot of respect for BMW over the past couple of years... they've really gone down hill in quality and certainly in customer support