I had this issue on my E90 3er. The blade was not fully seated in the arm correctly.

 

i went to my dealer today and they said sometimes they forget to install the right one on the right side. the right side of the wiper is actually longer than the left side and he said this could be the reason it keeps hitting the side of the window. he switched it around and problems solved.

 

Thanks, that seems to have done the trick for me. Will know for sure when we get a thunderstorm but for now just by eyeballing, it doesn't look like it will hit the side of the window.

 

+1 Switching the longer wiper to the right side fixed the issue for me as well, thanks!