what could by the reason that this func sends 2 reqs ?
```js
async saveProduct(cartoon) {
                this.order.err = null;
                this.order.success = null;
                const response = await fetch(
                    '/orders/{{ $order->id }}/add-product-to/' + cartoon.number, {
                        method: 'POST',
                        headers: {
                            'X-CSRF-Token': document.querySelector('input[name=_token]')
                                .value
                        },
                        body: JSON.stringify(this.order)
                    });
                if (response.ok) {
                    this.order.success = true;
                    this.order.err = null;
                    const product = await response.json();
                    const activeCartoon = this.order.cartoons.find(c => c.number == cartoon
                        .number);
                    // console.log(product);
                    activeCartoon.products.push({
                        number: product.packed_by_mfg_serial ? product.mfg_serial :
                            product.serial,
                        name: product.product
                    });
}
```

What is HTTP method in first request - OPTIONS maybe?

Can you put `console.log` in `saveProduct` function's first line to make sure the function gets called only once?