select-frame-set-input-focus fails to raise the frame

[Bob Weiner <rsw@gnu.org>]

I use:  Editor:      Emacs 27.0.50
        Hyperbole:   7.0.2
        Sys Type:    x86_64-apple-darwin16.7.0
        OS Type:     darwin
        Window Sys:  ns

(defun test ()
  (let ((depress-frame (selected-frame))
	(release-frame (make-frame)))
    (select-frame-set-input-focus depress-frame)
    ;; On MacOS, depress-frame is never raised to the top
    ;; of the frame stack and never is given input focus
    ;; after release-frame is created.
    (sit-for 4)
    (select-frame-set-input-focus release-frame)))

(test)

----------
If I call test, I get the behavior described in its comments, basically
only release-frame is ever raised and has input focus.  If I edebug
the function, then I get the behavior, I expect with each frame raised
and with input focus, first the depress-frame for 4 seconds and then
release-frame.

Is there something wrong in the test function or is there a problem in
select-frame-set-input-focus?

Bob