Hi,
I signed up with this forum (first time with ANY online forum) just to let you know that I am having the exact same problem with my 2013 Lexus ES 350. I am guessing this has something to do with the windshield being "acoustic". Please do share if you have managed a solution.
I had to go through the Lexus customer service process and they finally replaced the windshield; however, it is pretty much the same. I would say that it seems slight less noticeable during a bright sunny day at time. However, at night the stretch of light is still there and many cases from over 300 ft~ away it looks like an extra set of small/tiny jeep/truck lights on top the hood at the top windshield area. The dealership contacted me and asked me if it was any better and I told them what I just posted and would have expected the Lexus customer service to contact me by now. I have to follow up with a call to them. The part that really blows my mind is it doesn't seem to be many people having this issue but I saw it in a brand new 2013, same as mine, and it had the same issue. What are the odds of this that it is in two cars that I personally know of and the windshield replacement has the same issue! If you bark loud enough they will replace the windshield and if you get that done I would love to hear your results. Thanks Tom.