Confirmed in IE9 (latest version). When I press the
<enter> key after editing comment, clicking on the comment's edit link again does nothing.* I have to refresh the page to get the edit link to work again. Only affects the currently-edited comment, not other comments on the page.
The problem does not occur if I use the mouse to save the comment.
*Yes, I do in fact edit comments twice, often enough to make this inconvenient.