Surren in wet weather from 40 km/h

Dear Moose Friends, since long google and the moose doctor have not yet identified my surren, now would like to come back to you experts. It’s about my XC60 (1!) D4 automatic, year of construction 3/2017, approx. 35tkm Here is a video of the surren: This is how it occurs: I checked this: My guess is that a cover sucks full of water and pushes through the wind to a moving part. I would like to have your opinion – maybe someone else has the problem? Thank you & VG Frank