It apparently isn't just Boeing that can't keep all of the doors on their planes. This Diamond DA-40 lost its left side rear door shortly after takeoff from Buffalo (NY) on Monday, and had to make an emergency return back to the airport:
https://www.wgrz.com/article/news/lo...9-f40a87d0ef2a
https://www.wgrz.com/embeds/video/re...f285716/iframe