custom_args is not working when receiving an inbound parse webhook

[ds21194]

When sending an email to a customer, I'm using personalization as:

{
    "personalizations": [
        {
            "to": [..],
            "dynamic_template_data": {..},
            "custom_args": {"customer_id": "..."}
        }
    ]
}

But when i'm getting the inbound parse back on the webhook I defined, I'm not seeing anywhere the customer_id property, nor custom_args object. I tried to search for some examples on where should I search it on the response or how to debug, but didn't find nether.

Tnx for the help!