I traced the problem to what must have been a fluke in the autosaves for that page. Once I deleted the autosaves, I was able to edit the page. In reviewing the core code, I didn’t see anything that would cause the function to redirect to the listing of pages in the trash. FWIW, the post_name
name column looked like this before the delete:
6609-revision-v1
6609-revision-v1
6609-revision-v1
6609-revision-v1
6609-autosave-v1
6609-autosave-v1
6609-revision-v1