diff --git a/guix/derivations.scm b/guix/derivations.scm
index b95849727b..f842d26be8 100644
--- a/guix/derivations.scm
+++ b/guix/derivations.scm
@@ -658,8 +658,11 @@ derivation at FILE."
                                 (make-derivation-input hash sub-drvs))))
                            inputs))
               (drv    (make-derivation outputs
-                                       (sort (coalesce-duplicate-inputs inputs)
-                                             derivation-input<?)
+
+                                       ;; Note: INPUTS is already the result
+                                       ;; of 'coalesce-duplicate-inputs'.
+                                       (sort inputs derivation-input<?)
+
                                        sources
                                        system builder args env-vars
                                        #f)))