I had this same problem, only worse, with a brand new VW GTI I bought back in 2014.
Wipers would chatter in plain rain, smear, skip, etc.
Tried new wiper arms under warranty, different wiper blades from VW, Bosch, /Valeo SWF -everything!
To finally remedy the issue, I eventually figured out it must be the porters and PDI people hosing the car down in spray wax or using Rain-X or something prior to delivery.
Eventually I used a DA polisher with a German glass polishing compound to mechanically remove the film and it was good as new.
To this day I use home brew glass cleaning mixture for the outside glass comprising of 30% vinegar, distilled water, dawn dishsoap, and 91% alcohol.
Does a great job at removing the film from road spray, leaky trucks, and oily deposits.
If anyone is also looking at replacing the factory wipers, these Euro spec Bosch ones are excellent: https://a.co/d/7tBgVSj
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