Expound error when using fully-qualified symbol in let binding

ex.clj

(require '[clojure.core.specs.alpha])
(require '[clojure.spec.alpha :as s])
(require '[clojure.spec.test.alpha :as stest])
(require '[expound.alpha :as expound])
(set! s/*explain-out* (expound/custom-printer {:print-specs? false})) ; The "relevant specs" are very long, so let's omit them
(stest/instrument)

(let [foo/bar 42])

;; CompilerException clojure.lang.ExceptionInfo: Call to clojure.core/let did not conform to spec:
;; -- Spec failed --------------------
;; 
;;   ([foo/bar ...])
;;    ^^^^^^^
;;
;; should satisfy
;;
;;  simple-symbol?
;;
;; or
;;
;;  vector?
;;
;; or
;;
;;  coll?
;;
;; or
;;
;;  map?
;; 
;;
;;
;;-------------------------
;;Detected 1 error