It apparently is a manufacturing defect.... the exhaust comes uneven from factory. The only two suggestions are to play around with the hangers to even it out OR consider using zip ties to pull the exhaust closer to a more even point, there should be some holes or hangers around the exhaust for you to do that, but I just let it go as is, it doesn't bother me that much anymore.
I saw your post regarding your F sport exhaust being slightly uneven. Did you ever get that fixed? I just installed my F sport exhaust and have the same problem. I went to Lexus and a muffler shop to see if they can even it out but no luck.
Hope you were able to fix it and give me some insight on how I can too.