Google Cloud Tasks not executing tasks randomly - google-cloud-platform

Question

Google Cloud Tasks seems to be unreliable some times. I've added a bunch of tasks and sometimes those are not getting executed.
When I checked the console, it shows '11 Tasks in Queue'. However, those tasks are not listed below (usually it shows correctly).
Here is how I've created the queue (upsert):
const client = require('./client');
module.exports = async (queue_name, concurrent) => {
return client.updateQueue({
queue: {
name: client.queuePath(
process.env.GCP_PROJECT,
process.env.GCP_QUEUE_LOCATION,
queue_name,
),
rateLimits: {
maxConcurrentDispatches: concurrent,
maxDispatchesPerSecond: concurrent,
maxBurstSize: 100,
},
retryConfig: {
maxAttempts: 3,
unlimitedAttempts: false,
maxRetryDuration: {
seconds: 3600,
},
minBackoff: {
seconds: 60,
},
maxBackoff: {
seconds: 300,
},
maxDoublings: 3,
},
},
});
};
and here is how I'm adding tasks:
const client = require('./client');
module.exports = async (queue_name, url, config) => {
return client.createTask({
parent: client.queuePath(
process.env.GCP_PROJECT,
process.env.GCP_QUEUE_LOCATION,
queue_name,
),
task: {
httpRequest: {
httpMethod: 'POST',
headers: {
'Content-Type': 'application/json',
},
url: `${process.env.OPTIMIZER_URL}/optimize-page`,
body: Buffer.from(JSON.stringify({ url, config })).toString(
'base64',
),
},
},
});
};
The same code works sometimes and sometimes it just got stuck at executing!