While that error is fixed, we still have this byte compilation warning:

org-capture.el:1586:1:Warning: Unused lexical variable ‘first-value’

I haven't used pcase extensively, but based on the warning, the below
doesn't work as intended in the compiled elc:

   ((or "C" "L")
    (let ((insert-fun (if (equal key "C") #'insert
(lambda (s) (org-insert-link 0 s))))
  (first-value (car org-capture--clipboards)))
      (pcase (length org-capture--clipboards)
(`nil nil)
(`(,value) (funcall insert-fun value))
(`(,first-value . ,_)
 (funcall insert-fun
  (read-string "Clipboard/kill value: "
first-value                                                ; Based on the
warning, does it mean that the value of first-value is not picked from the
value calculated in the let form above?
'org-capture--clipboards
first-value)))                                             ; And the same
here
(_ (error "Invalid `org-capture--clipboards' value: %S"
  org-capture--clipboards)))))
-- 

Kaushal Modi