Take http://en.wikipedia.org/wiki/File:Areva1.jpg for example. On May 5, 2006, Hardouin uploaded the first revision. Then on December 1, 2009, RandomStringOfCharacters uploaded a second revision, and on December 21, 2009, Angusmclellan deleted the first revision.
Now I went back to undelete the first revision (using Special:Undelete). I entered a reason in the "Reason" box and clicked "Restore," but I got an error message "Undelete failed; someone else may have undeleted the page first." However, the revision did get undeleted, though no entry was left in the deletion log.
This may be a duplicate of 28632, but as I am not sure, I am filing this as a separate bug.
Version: 1.20.x
Severity: normal