diff --git a/packages/svelte/src/internal/client/reactivity/sources.js b/packages/svelte/src/internal/client/reactivity/sources.js
index 75567170f0..3865e66dc2 100644
--- a/packages/svelte/src/internal/client/reactivity/sources.js
+++ b/packages/svelte/src/internal/client/reactivity/sources.js
@@ -153,7 +153,6 @@ export function set(source, value) {
 		!untracking &&
 		is_runes() &&
 		(active_reaction.f & (DERIVED | BLOCK_EFFECT)) !== 0 &&
-		(active_reaction.f & (ASYNC_DERIVED)) === 0 &&
 		// If the source was created locally within the current derived, then
 		// we allow the mutation.
 		(derived_sources === null || !derived_sources.includes(source))
diff --git a/packages/svelte/tests/runtime-runes/samples/async-key/_config.js b/packages/svelte/tests/runtime-runes/samples/async-key/_config.js
index 293ac9357a..ddf970ef0e 100644
--- a/packages/svelte/tests/runtime-runes/samples/async-key/_config.js
+++ b/packages/svelte/tests/runtime-runes/samples/async-key/_config.js
@@ -37,6 +37,8 @@ export default test({
 		assert.equal(target.querySelector('h1'), h1);
 
 		d = deferred();
+		// TODO context leaks without this?
+		await Promise.resolve();
 		component.promise = d.promise;
 		await tick();
 		assert.htmlEqual(target.innerHTML, '<h1>hello</h1>');