(Or maybe the suggested edits interfere with the dupe link, I guess that also works.)
This is something I've seen happening a couple times, such as here.
When an edit is suggested before, and reviewed after the question is closed as a duplicate, the edit will appear to remove the "Possible Duplicate" box that is automatically added by Community.
This happens due to a clashing edit situation that is usually impossible — normal users can't suggest edits while another one is already pending, and those with edit rights are forced to approve or reject it first.
However, Community is highly rude and just performs the edit anyway.