diff --git a/guix-data-service/utils.scm b/guix-data-service/utils.scm
index c5c6bdf..c5c89a4 100644
--- a/guix-data-service/utils.scm
+++ b/guix-data-service/utils.scm
@@ -185,7 +185,7 @@
                (head (defer-to-thread-pool-channel
                        (lambda ()
                          (apply proc heads)))))
-           (cons (fetch-result-of-defered-thunk head) tail)))
+           (cons (fetch-result-of-defered-thunks head) tail)))
         (_
          '())))))