diff --git a/index.bs b/index.bs
index 7c11b834..0440d073 100644
--- a/index.bs
+++ b/index.bs
@@ -818,8 +818,9 @@ spec: storage; urlPrefix: https://storage.spec.whatwg.org/
         1. Let |promise| be a new <a>promise</a>.
         1. Run the following substeps <a>in parallel</a>:
             1. Let |registration| be the result of running <a>Match Service Worker Registration</a> given |storage key| and |clientURL|.
-            1. If |registration| is null, resolve |promise| with undefined and abort these steps.
-            1. Resolve |promise| with the result of [=getting the service worker registration object=] that represents |registration| in |promise|'s [=relevant settings object=].
+            1. [=Queue a task=] on |promise|'s [=relevant settings object=]'s [=responsible event loop=], using the [=DOM manipulation task source=], to run the following steps:
+                1. If |registration| is null, resolve |promise| with undefined and abort these steps.
+                1. Resolve |promise| with the result of [=getting the service worker registration object=] that represents |registration| in |promise|'s [=relevant settings object=].
         1. Return |promise|.
     </section>