diff --git a/src/utils/Idler.tsx b/src/utils/Idler.tsx
index 21a994cf5..588d63fa3 100644
--- a/src/utils/Idler.tsx
+++ b/src/utils/Idler.tsx
@@ -25,7 +25,7 @@ export class Idler implements BaseIdler {
     return this.kill || performance.now() - this.lastIdle > this.interval;
   }
 
-  idle(): Promise<void> {
+  async idle(): Promise<void> {
     if (this.kill) {
       throw new CancelledPromiseError('Idler got killed');
     }
@@ -34,7 +34,7 @@ export class Idler implements BaseIdler {
       this.lastIdle = now;
       return new Promise(resolve => setTimeout(resolve, 0));
     }
-    return Promise.resolve();
+    return undefined;
   }
 
   cancel() {
diff --git a/src/utils/serialization.tsx b/src/utils/serialization.tsx
index 569c44eb2..a3afe89fb 100644
--- a/src/utils/serialization.tsx
+++ b/src/utils/serialization.tsx
@@ -136,7 +136,7 @@ export async function makeObjectSerializable(
   let prevStackLength = stack.length;
   let accumulator = prevStackLength;
   while (stack.length > 0) {
-    if (idler) {
+    if (idler && idler.shouldIdle()) {
       await idler.idle();
     }
     const element = stack[stack.length - 1];