I'm also encountering this. Feedback: FB13554487, including logs and project source, and a link to the failing build. Thanks.

I'm not sure what to make of DocumentGroup. It seems like the way we're supposed to create a document-based SwiftUI app, but it's missing major pieces of functionality. For example, there's no way to do state restoration. No way to run tests that create and open documents. No clear way to present first-run UI or let the user pick a document type to create. Is everyone rolling their own alternative or how are people handling this?