Sometimes 'Only absolute URLs are supported' error

[NielsHavermans]

Hi,

I'm using nuxt/http to fetch data from my API using a proxy. This for a replacement of axios due to CORS errors.
Sometimes, not every time, I get this error during fetch ($fetchState.error): "message": "Only absolute URLs are supported", "statusCode": 500
This in dev and in build.

Fetch request
async fetch() {
const res = await fetch(
'/product-api/products?id=XX&category=XX
}
this.product = await res.json()
}

nuxt.config.js
http: {
retry: 1,
proxy: true,
prefix: "/product-api",
},
proxy: {
'/product-api': {
target: 'https://<api_url>/',
pathRewrite: {'^/product-api': ''}
}
}

Does someone has the same problem, or is there anything wrong in my approach?
Thanks!