diff --git a/containers/libreportal/frontend/js/components/app/app-tabbed-manager.js b/containers/libreportal/frontend/js/components/app/app-tabbed-manager.js
index f6fe575..8cae508 100755
--- a/containers/libreportal/frontend/js/components/app/app-tabbed-manager.js
+++ b/containers/libreportal/frontend/js/components/app/app-tabbed-manager.js
@@ -708,11 +708,16 @@ class AppTabbedManager {
       this.switchTab('tasks');
     }
     
-    // Monitor URL changes for app navigation
-    this.setupURLMonitoring();
-    
-    // Listen for task creation events
-    this.setupTaskEventListeners();
+    // Monitor URL changes for app navigation + listen for task events. These
+    // add window-level listeners (popstate, taskCreated/Completed/Updated), so
+    // bind them ONCE for the lifetime of this singleton — initialize() re-runs
+    // on every /app navigation (the `initialized` flag is never set true), and
+    // without this guard each visit stacked another set of window listeners.
+    if (!this._listenersWired) {
+      this._listenersWired = true;
+      this.setupURLMonitoring();
+      this.setupTaskEventListeners();
+    }
     
     // Set initial active tab (only if no task parameter)
     if (!taskId) {