I have the same problem.. do I lose my warranty if I do it so? I’m still in the returning period.I had a similar problem with my new MBA. I solved it my loosening the bottom screws slightly across the board and making sure they were tight but not overtightened. It sits flat on every surface now.
As a sidenote, my 16" MBP also wobbled slightly, but because it was heavier, it was much more difficult to notice.