Bug in looking-at?

[Lennart Borgman]

Second time today I think I have found a bug... What should I say... 
Hope this one is ok ;-)

(defun bug-looking-at()
 "Instructions for showing the possible bug:
1. Place the point before \(interactive\) and run this function.
  The first looking-at succeeds, the second fails.
2. Then copy the last (looking-at ...), place point as before and run 
with M-S-:.
  It should fail to match again.
3. Now recall this in M-S-: and add character s last in the regexp.
  This time it should match. Try removing the s again..."
 (interactive)
 (unless (looking-at "(interactive)")
   (error "Please put the point at \(interactive\)"))
 (message "Second (looking-at ...) => %s" (looking-at 
"(interactive)[[:space:]]+(unles")))

I am doing this on w32, Emacs from 9 aug, emacs -Q.