diff --git a/plug-api/lib/json.test.ts b/plug-api/lib/json.test.ts
index 7127164b..d0969ab7 100644
--- a/plug-api/lib/json.test.ts
+++ b/plug-api/lib/json.test.ts
@@ -22,9 +22,6 @@ Deno.test("JSON utils", () => {
   assertEquals(cleanupJSON({ a: [{ "a.b": 1 }] }), {
     a: [{ a: { b: 1 } }],
   });
-  assertEquals(
-    cleanupJSON(new Date("2023-05-13T12:30:00Z")),
-    "2023-05-13T12:30:00.000Z",
-  );
+
   assertEquals(cleanupJSON(new Date("2023-05-03T00:00:00Z")), "2023-05-03");
 });
diff --git a/plug-api/lib/json.ts b/plug-api/lib/json.ts
index f26b7000..dd2b5cf4 100644
--- a/plug-api/lib/json.ts
+++ b/plug-api/lib/json.ts
@@ -60,7 +60,7 @@ export function cleanStringDate(d: Date): string {
       String(d.getMonth() + 1).padStart(2, "0") + "-" +
       String(d.getDate()).padStart(2, "0");
   } else {
-    return localDateString(d);
+    return d.toISOString();
   }
 }