diff --git a/jupyter-org-client.el b/jupyter-org-client.el
index eedb658..4d92a42 100644
--- a/jupyter-org-client.el
+++ b/jupyter-org-client.el
@@ -1268,9 +1268,15 @@ buffer."
 ;;; org-babel functions
 ;; These are meant to be called by `org-babel-execute:jupyter'
 
-(defun jupyter-org-insert-async-id (req)
-  "Insert the ID of REQ.
-Meant to be used as the return value of
+(defun jupyter-org-pending-async-results (req)
+  "Finish up bookkeeping for an asynchronous source block REQ.
+Setup `org-babel-after-execute-hook' to insert the ID of REQ as
+the result of the associated source block, to signify that the
+results of REQ are pending, and run any other hook functions that
+were present before this function was called.
+
+This function always returns nil and is intended to be used as
+the return value for asynchronous Jupyter source blocks in
 `org-babel-execute:jupyter'."
   (prog1 nil
     (let ((log-max message-log-max)
@@ -1278,12 +1284,12 @@ Meant to be used as the return value of
           (id (jupyter-org-scalar (jupyter-org-request-id req))))
       (setq message-log-max nil)
       (setq org-babel-after-execute-hook
-            (lambda ()
-              (setq message-log-max log-max)
-              (unwind-protect
-                  (jupyter-org--add-result req id)
-                (setq org-babel-after-execute-hook hook)
-                (run-hooks 'org-babel-after-execute-hook)))))))
+            (list (lambda ()
+                    (setq message-log-max log-max)
+                    (unwind-protect
+                        (jupyter-org--add-result req id)
+                      (setq org-babel-after-execute-hook hook)
+                      (run-hooks 'org-babel-after-execute-hook))))))))
 
 (defun jupyter-org--coalesce-stream-results (results)
   "Return RESULTS with all contiguous stream results concatenated.
diff --git a/ob-jupyter.el b/ob-jupyter.el
index 954c0b1..68b681c 100644
--- a/ob-jupyter.el
+++ b/ob-jupyter.el
@@ -304,7 +304,7 @@ the PARAMS alist."
         (when (bound-and-true-p org-export-current-backend)
           (add-hook 'org-babel-after-execute-hook #'sync-on-export t t))
         (if (jupyter-org-request-inline-block-p req) ""
-          (jupyter-org-insert-async-id req))))
+          (jupyter-org-pending-async-results req))))
      (t
       (let ((result-params (assq :result-params params)))
         (when (and (member "file" result-params)