batch reosolvers bug?

pathom3 batch error

(def db {:a {1 {:a/id 1 :a/code "a-1"}
               2 {:a/id 2 :a/code "a-2"}}
           :f {1 {:f/id 1 :f/code "f-1"}
               2 {:f/id 2 :f/code "f-2"}}
           :b {1 [{:f/id 1}]}
           :c {1 [{:f/id 2}]}})

(pco/defresolver a [input]
    {::pco/input  [:a/id]
     ::pco/output [:a/id :a/code]
     ::pco/batch? true}
    (mapv #(get-in db [:a (:a/id %)]) input))

(pco/defresolver f [input]
  {::pco/input  [:f/id]
     ::pco/output [:f/id :f/code]}
    (get-in db [:f (:f/id input)]))

;; this is the batched version of the resolver above
(pco/defresolver f' [input]
    {::pco/input  [:f/id]
     ::pco/output [:f/id :f/code]
     ::pco/batch? true}
    (mapv #(get-in db [:f (:f/id %)]) input))

(pco/defresolver b [input]
    {::pco/input  [:a/id]
     ::pco/output [{:a/b [:f/id]}]
     ::pco/batch? true}
    (mapv (fn [{:a/keys [id]}]
           {:a/b (get-in db [:b id])}) input))

(pco/defresolver c [input]
    {::pco/input  [:a/id]
     ::pco/output [{:a/c [:f/id]}]
     ::pco/batch? true}
    (mapv (fn [{:a/keys [id]}]
           {:a/c (get-in db [:c id])}) input))

;; non batched f resolver
(p.eql/process (pci/register [a f b c])
                 [{[:a/id 1] [:a/code {:a/b [:f/id :f/code]} {:a/c [:f/id :f/code]}]}])
 ;; => output: 
 ;; {[:a/id 1]
 ;; {:a/code "a-1"
 ;;  :a/b    [{:f/id 1 :f/code "f-1"}]
 ;;  :a/c    [{:f/id 2 :f/code "f-2"}]}}

 ;; batched f resolver
   (p.eql/process (pci/register [a f'  b c])
                 [{[:a/id 1] [:a/code {:a/b [:f/id :f/code]} {:a/c [:f/id :f/code]}]}])

 ;; => output: 
 ;; {[:a/id 1]
 ;; {:a/code "a-1"
 ;;  :a/b    [{:f/id 1 :f/code "f-1"}]
 ;;  :a/c    [{:f/id 2}]}} ;; notice the missing :f/code here