Has any one recently encountered this? I have been stuck with this for so long and it is so frustrating.
I am right now doing this: Create a task, and execute onTaskDispatched at the schedule time which just logs in the consol for now.

I don't get the permission_denied error, so my service account has all t he permission. I only get INVALID_ARGUMENT

This is my code snippet:

// [NOTIFICATION TASK CREATION START]
  const scheduledTime = notification.scheduledTime.toDate();
  const now = new Date();


  // Use Cloud Tasks
  const client = await getCloudTasksClient();
  const parent = client.queuePath(PROJECT_ID, LOCATION, QUEUE_NAME);
  const url = `https://${LOCATION}-${PROJECT_ID}.cloudfunctions.net/processScheduledNotification`;

  // Calculate schedule time
  const date_diff_in_seconds = (scheduledTime.getTime() - now.getTime()) / 1000;
  const MAX_SCHEDULE_LIMIT = 30 * 24 * 60 * 60; // 30 days in seconds

  let scheduledSeconds;
  // If scheduled time is in the past or very near future (< 5 mins), schedule for 30 seconds from now
  // Otherwise, schedule for the calculated time, capped at MAX_SCHEDULE_LIMIT
  if (date_diff_in_seconds <= 0 || date_diff_in_seconds < 300) {
    scheduledSeconds = Math.floor(Date.now() / 1000) + 30;
  } else {
    scheduledSeconds = Math.floor(Math.min(date_diff_in_seconds, MAX_SCHEDULE_LIMIT) + Date.now() / 1000);
  }

const payload = JSON.stringify({ notificationId: notification.id })
  const body = Buffer.from(payload).toString('base64')
  // Create the task payload - send only the notification ID
  const task = {
    httpRequest: {
      httpMethod: 'POST',
      url,
      headers: {
        'Content-Type': 'application/json',
      },
      // Send only the notification ID in the body
      body:body,
      oidcToken: {
        serviceAccountEmail: `{PROJECT-NUMBER}[email protected]`, // Use PROJECT_ID variable
        audience: url  // To my service function below
      }
    },
    scheduleTime: {
      seconds: scheduledSeconds,
      nanos: 0
    }
  };
  const [response] = await client.createTask({ parent, task });

/**
 * Cloud Task handler for processing scheduled notifications
 */
export const processScheduledNotification = onTaskDispatched({
  retryConfig: {
    maxAttempts: 5,
    minBackoffSeconds: 30,
  },
  queueName: 'notification-queue',
}, async (data) => {
  console.log('⏲️ Received Cloud Task for scheduled notification');
  console.log('Received req object:', data); 
});

What am I doing wrong? Any pointers? Whats up with gprc as well? i think its correctly set up. Please help.