Here is the original discussion we disscusses.
https://github.com/jkitchin/org-ref/issues/433

And Here is the patch:

#+BEGIN_SRC diff
modified   lisp/org.el
@@ -9730,7 +9730,7 @@ active region."
      (setq sfuns
    (delq
     nil (mapcar (lambda (f)
-  (let (fs) (if (funcall f) (push f fs))))
+  (let (fs) (if (and (stringp f) (funcall f)) (push f fs))))
  (org-store-link-functions)))
    sfunsn (mapcar (lambda (fu) (symbol-name (car fu))) sfuns))
      (or (and (cdr sfuns)
#+END_SRC

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