Payment Details not showing up using Paypal rest API

[Cypher]

Hi, I've made a payment process using node.js and paypal's Rest API. Finally I could achieve to create and execute a payment, but, my payment description is blank, I already try all about payment and transaction object following the documentation:
https://developer.paypal.com/webapps/developer/docs/api/#payments

I had to hardcode it in the description attribute but it looks weird.

You can check it in here, just fill the form and submit:
https://www.esla.pro/donaciones/

Payment object code:

{
    "intent": "sale",
    "payer": {
        "payment_method": "paypal"
    },
    "redirect_urls": {
        "return_url": "https://www.esla.pro/requests/req_donacion.php?accion=exito",
        "cancel_url": "https://www.esla.pro/donaciones/"
    },
    "transactions": [{
        "amount": {
            "total": options.cantidad,
            "currency": options.moneda,
            "details": {
                "subtotal": options.cantidad
            }
        },
       "description": "Total: $" + options.cantidad + " " + options.moneda
    }]
}

Any bit of help is very appreciated, thanks for your time.