I reported the issue at my Twitter. See thread here https://twitter.com/aleixmorgadas/status/1365693737515560964
You can see the App running to check the behavior here https://nuxt-netlify-form-issue.netlify.app/
See solution at branch solution https://github.com/aleixmorgadas/nuxt-netlify-form-issue/tree/solution
# install dependencies
$ yarn install
# serve with hot reload at localhost:3000
$ yarn dev
# build for production and launch server
$ yarn build
$ yarn start
# generate static project
$ yarn generate
For detailed explanation on how things work, check out Nuxt.js docs.