Imagine this scenario (this has happened to me, but I can't find any examples ATM):
I come across a post that needs editing, for whatever reason, and make necessary changes to it. After submitting my edit, I notice that there is a pending edit that duplicates the changes that I just made (or makes some of the changes, but not others).
Should the pending edit be rejected? I'm often hesitant to reject it because that will reflect negatively on the editor, even though its a perfectly valid edit that just happens to duplicate what I already did (or overwrite some of my changes, through no fault of the editor, since we submitted the edits at the same time.)