Using button-label in pcase

[uzibalqa]

Want to print some text as a result of clicking a button.  With the code below
I end up with

(wrong-type-argument integer-or-marker-p nil)
  buffer-substring-no-properties(nil nil)
  button-label(#<overlay in no buffer>)
  (let* ((val (button-label button))) (if (equal val '"[FA]") (let nil (insert 
qrh-c))))
  (closure ((button . #<overlay in no buffer>)) nil (let* ((val (button-label 
button))) (if (equal val '"[FA]") (let nil (insert qrh-c)))))()
  help--window-setup("*Help*" (closure ((button . #<overlay in no buffer>)) nil 
(let* ((val (button-label button))) (if (equal val '"[FA]") (let nil (insert 
qrh-c))))))
  qrh-b(#<overlay in no buffer>)
  button-activate(#<overlay in no buffer> t)
  push-button(3 t)

What is going on.  Is there a fix?

(defconst qrh-c "[FA] Some Text")

(defun qrh-b (button)
  "Prints information about how to install emacs."
  (with-help-window (help-buffer)
    (pcase (button-label button)
      ("[FA]" (insert qrh-c))) ))

(defun qrh-a ()
  "Prints information about how to install emacs."
  (interactive)
  (with-help-window (help-buffer)
    (insert-button "[FC]"
      'action 'qrh-b 'follow-link t) ))