El conjunto de notificaciones AutoCancel (verdadero) no funciona si se hace clic en Acción

Tengo una notificación con una acción dentro de ella. Cuando toco la notificación, se elimina de la lista. Sin embargo, cuando hago clic en la Acción, completa con éxito la Acción (es decir, hace una llamada), pero cuando vuelvo a la lista de notificaciones, permanece allí. Código relativo del AlarmReceiver:

public class AlarmReceiver extends BroadcastReceiver {
Meeting meeting;

/**
 * Handle received notifications about meetings that are going to start
 */
@Override
public void onReceive(Context context, Intent intent) {

    // Get extras from the notification intent
    Bundle extras = intent.getExtras();
    this.meeting = extras.getParcelable("MeetingParcel");

    // build notification pending intent to go to the details page when click on the body of the notification
    Intent notificationIntent = new Intent(context, MeetingDetails.class);
    notificationIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    notificationIntent.putExtra("MeetingParcel", meeting);      // send meeting that we received to the MeetingDetails class
    notificationIntent.putExtra("notificationIntent", true);    // flag to know where the details screen is opening from

    PendingIntent pIntent = PendingIntent.getActivity(context, 0, notificationIntent, 0);

    // build intents for the call now button
    Intent phoneCall = Call._callIntent(meeting);
    if (phoneCall != null) {

        PendingIntent phoneCallIntent = PendingIntent.getActivity(context, 0, phoneCall, PendingIntent.FLAG_CANCEL_CURRENT);

        int flags = Notification.FLAG_AUTO_CANCEL;

        // build notification object
        NotificationCompat.Builder builder = new NotificationCompat.Builder(context);
        Notification notification = builder.setContentTitle("Call In")
                .setContentText(intent.getStringExtra("contextText"))
                .setTicker("Call In Notification")
                .setColor(ContextCompat.getColor(context, R.color.colorBluePrimary))
                .setAutoCancel(true)                    // will remove notification from the status bar once is clicked
                .setDefaults(Notification.DEFAULT_ALL)  // Default vibration, default sound, default LED: requires VIBRATE permission
                .setSmallIcon(R.drawable.icon_notifications)
                .setStyle(new NotificationCompat.BigTextStyle()
                        .bigText(meeting.description))
                .addAction(R.drawable.icon_device, "Call Now", phoneCallIntent)
                .setCategory(Notification.CATEGORY_EVENT)   // handle notification as a calendar event
                .setPriority(Notification.PRIORITY_HIGH)    // this will show the notification floating. Priority is high because it is a time sensitive notification
                .setContentIntent(pIntent).build();

        notification.flags = flags;

        // tell the notification manager to notify the user with our custom notification
        NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
        notificationManager.notify(0, notification);
    }
  }
}