Issue #3487951: Some event listeners is not added with addListener

Closes #3487951

src/EventDispatcher/TraceableEventDispatcher.php

@@ -180,6 +180,10 @@ class TraceableEventDispatcher implements EventDispatcherTraceableInterface {
       return;
     }
 
+    if (!isset($this->notCalledListeners[$event_name][$priority])) {
+      return;
+    }
+
     foreach ($this->notCalledListeners[$event_name][$priority] as $key => $listener) {
       if ($listener['callable'][0] instanceof \Closure) {
         $listener['callable'][0] = $listener['callable'][0]();