reported on en.wp by Atethnekos:
"So I put a space and then a backspace. Go to save, review changes to check and make sure it is a null edit, then it goes to this "processing" dialogue but then it shows "Could not start the review because your revision matches the latest version of this page." So then I press the little back link on the dialogue, but it just goes back to the processing dialogue. If the page is small, the processing is really quick, so before I can even press back again, it goes back to the "Could not start" warning message. Even if I do manage to press the back a second time quickly, it will only stay at the save dialogue for a split second and then again bring me to the warning message, although then pressing back does take me to the save dialogue securely. FF 23.0.1 Win7"
I've confirmed this in Firefox 23.0 on Linux.
The issue is with the < link only. Clicking the ^ does return you to the editing screen as expected.