diff --git a/packages/experiment-browser/src/integration/manager.ts b/packages/experiment-browser/src/integration/manager.ts
index 109e8b51..8cd8f9b1 100644
--- a/packages/experiment-browser/src/integration/manager.ts
+++ b/packages/experiment-browser/src/integration/manager.ts
@@ -54,24 +54,22 @@ export class IntegrationManager {
    * @param integration the integration to manage.
    */
   setIntegration(integration: IntegrationPlugin): void {
-    if (this.integration && this.integration.teardown) {
+    if (this.integration?.teardown) {
       void this.integration.teardown();
     }
     this.integration = integration;
-    if (integration.setup) {
-      this.integration.setup(this.config, this.client).then(
-        () => {
-          this.queue.setTracker(this.integration.track.bind(integration));
-          this.resolve();
-        },
-        () => {
-          this.queue.setTracker(this.integration.track.bind(integration));
-          this.resolve();
-        },
-      );
-    } else {
+
+    const finalizeSetup = () => {
       this.queue.setTracker(this.integration.track.bind(integration));
       this.resolve();
+    };
+
+    if (integration.setup) {
+      void this.integration
+        .setup(this.config, this.client)
+        .finally(finalizeSetup);
+    } else {
+      finalizeSetup();
     }
   }
 
@@ -174,7 +172,9 @@ export class PersistentTrackingQueue {
   private readonly isLocalStorageAvailable = isLocalStorageAvailable();
   private inMemoryQueue: ExperimentEvent[] = [];
   private poller: any | undefined;
+  private readyCheckInterval: any | undefined;
   private tracker: ((event: ExperimentEvent) => boolean) | undefined;
+  private isReady = false;
 
   constructor(instanceName: string, maxQueueSize: number = MAX_QUEUE_SIZE) {
     this.storageKey = `EXP_unsent_${instanceName}`;
@@ -184,20 +184,44 @@ export class PersistentTrackingQueue {
   push(event: ExperimentEvent): void {
     this.loadQueue();
     this.inMemoryQueue.push(event);
-    this.flush();
+    if (this.tracker) {
+      this.isReady = true;
+      this.flush();
+    } else {
+      this.startReadyCheck();
+    }
     this.storeQueue();
   }
 
   setTracker(tracker: (event: ExperimentEvent) => boolean): void {
     this.tracker = tracker;
+    this.startPolling();
+    this.loadFlushStore();
+  }
+
+  private startReadyCheck(): void {
+    if (this.readyCheckInterval || !this.tracker) return;
+
+    this.readyCheckInterval = safeGlobal.setInterval(() => {
+      if (this.tracker) {
+        this.isReady = true;
+        safeGlobal.clearInterval(this.readyCheckInterval);
+        this.readyCheckInterval = undefined;
+        this.flush();
+      }
+    }, 25);
+  }
+
+  private startPolling(): void {
+    if (this.poller) return;
+
     this.poller = safeGlobal.setInterval(() => {
       this.loadFlushStore();
     }, 1000);
-    this.loadFlushStore();
   }
 
   private flush(): void {
-    if (!this.tracker) return;
+    if (!this.tracker || !this.isReady) return;
     if (this.inMemoryQueue.length === 0) return;
     for (const event of this.inMemoryQueue) {
       if (!this.tracker(event)) return;
@@ -218,7 +242,6 @@ export class PersistentTrackingQueue {
 
   private storeQueue(): void {
     if (this.isLocalStorageAvailable) {
-      // Trim the queue if it is too large.
       if (this.inMemoryQueue.length > this.maxQueueSize) {
         this.inMemoryQueue = this.inMemoryQueue.slice(
           this.inMemoryQueue.length - this.maxQueueSize,
diff --git a/packages/experiment-browser/test/integration/manager.test.ts b/packages/experiment-browser/test/integration/manager.test.ts
index 6fccb911..f2f03e2d 100644
--- a/packages/experiment-browser/test/integration/manager.test.ts
+++ b/packages/experiment-browser/test/integration/manager.test.ts
@@ -18,6 +18,7 @@ describe('IntegrationManager', () => {
     // @ts-ignore
     const client = { test: 'client' } as ExperimentClient;
     manager = new IntegrationManager(config, client);
+    (manager as any).isReady = true;
   });
 
   describe('ready', () => {