For anyone with a similar problem:
Ironically, this problem happened to me right after I had my windshield wipers replaced at the dealership. We were totally frustrated because we just couldn't figure out the cause. Until one day, as usual, I found a cat on the hood (I live in Turkey, where this happens a lot). The idea popped into my head that the little cat had probably tampered with the windshield wipers. I was right; it had used one of the wipers as a scratching toy and bitten off a piece of the wiper's silicone. So, if you hear something like this from future customers, it will always be a silicone issue .