I have noticed that the front windscreen washer bleeds vapour into the cabin unless the air is in recirculation mode. As many such fluids contain methanol this is not the best addition to the interior air quality. The BMW service counter seemed to know about the effect as the cabin air intake is adjacent to the fluid jets. Perhaps owners should be told about this and advised not to use methanol based fluids. This seems to be a design error and not readily changed. I have never experienced this with previous cars.