Has anyone experienced condensation forming on the exterior of the windshield on 2009 Mercedes-Benz ML320 BLUETEC

directly above the defrost vents. I have never encountered this in any other auto I have owned, and wonder if it is common, like MB indicates it is.

2 answers
maybe your heater core is leaking or vent tube is clogged
good old germans. seek diag as to issue and get est.poss heater core or other coolant leak