Started to see this with a an app I uploaded recently. It still processes, but is it anything to be concerned about?
Invalid Document Configuration - Document Based Apps should support either the Document Browser (UISupportsDocumentBrowser = YES) or implement Open In Place (LSSupportsOpeningDocumentsInPlace = YES/NO). Visit https://developer.apple.com/document-based-apps/ for more information.
I'll try adding this to my next build and report back.
One other item of note, and for what it's worth - this message starting showing up some time between June 17 and Sept 13. The app was using DocumentInteraction prior to June 17 as well. (I had taken a break from working on it - sorry I can't be more precise with the dates.)