I make an edit, and type something in the Edit Summary box. Then I realise five minutes later that my edit summary was wrong. So I click on "edited 5 mins ago", and then on "edit" (with mouse-over text "edit this revision"). So now I can edit my edit. But if I only change the Edit Summary, my change gets lost. Is this a bug?
Test edit 1 (see comments) Test edit 2 (see comments)