I just had this edited question come up for review
It looks like the editor made a small change and added a question of his own. But he also removed the system message that the question was closed as a duplicate.
This is seen in the revision history here
but is not visible in the edit review. So, of course, the edit was approved!
I propose that all edits to a post are shown in the edit review. :-)
Apparently all proposed edits are shown, but in that case the approved edit is all that should be applied to the post and nothing more.
I now see that this is somewhat similar to earlier "Who did the edit?" questions, where some edits show up on the wrong user.