The example of 'until-procedure' in final document is wrong. See:

(let ((i 10))
  (until-procedure
    (lambda ()
      (set! i (- i 1))
      (display i)
       (> i 0)))) => unspecified ;prints "9876543210"

It should be:

(let ((i 10))
  (until-procedure
    (lambda ()
      (set! i (- i 1))
      (display i)
       (< i 1))))

Regards