If you are reffering to the brake light located under the rear glass, i have noticed that the plastic around the bulb housing has a bit of melted plastic. At the time the bulb burned out and i opened it for a replacement, and seen the melted plastic (nothing extreme). I just replaced the bulb and popped it back i place. Havent checked it since (been over 2 years).
Can anyone else chime in on this one?
E39 540i Sport