This question already has an answer here:
No, this isn't another user improving the edit. Sorry to those who thought they could get easy rep :)
Over on Physics.SE, I made a suggested edit - #17486.
I admit that it wasn't the best edit (I made a mistake in the formatting), but the Community user just came along and casted a binding reject vote.
Now, I know that the Community user does this when I am reviewing edits on sites where I'm 2k (here and SO), and I click the Improve button and deselect the 'this edit is helpful' checkbox.
When this happens, however, the Community user rejects the edit, then another entry for the user that chose the improve option is also show above the binding reject vote.
That's not what happened here - I suggested the edit at 20:45, and the CU rejected it at... 20:45. No entry for someone clicking the Improve button.