Breakpoint bug?

I think I've discovered a bug in LWW 4.3.7. After evaluating

(defun test ()
  (let (*spec*)
    (declare (special *spec*))
    (print *spec*)))

where *spec* is NOT defined globally by defvar, I get an error whenever I try to set breakpoint anywhere in the code. The error does not occur when *spec* is defined globally by defvar.

Any comments?

Michal