URL is not appending the port number

So I am using laravel and Browsersync for live reloading. In my webpack I have the following:

mix.js('resources/assets/js/app.js', 'public/js')
   .postCss('resources/assets/css/app.css', 'public/css', [
       tailwindcss('./tailwind.js')
   ])
    .browserSync(
    {
        proxy: 'http://twitter.test/',
        host: 'twitter.test',
        open: 'external'
    });

This makes my webpage: http://twitter.test:3000, so in my blade file I can print my urls like so:

routes = {
    'index': '',
    'store': '',
    'statuses': ''
}

Which gives me the following:

routes = {
    'index': '//twitter.test:3000/timeline',
    'store': '//twitter.test:3000/timeline',
    'statuses': '//twitter.test:3000/timeline'
}

Notce the :3000 port is in the URLS, which is what I want... Now if I go to my controller, and DD

dd(route("timeline.index"));

I get the following (which is expected; but note I am DD, not echoing)

"//twitter.test:3000/timeline"

BUT Now, if I change it to echo, like so:

echo route("timeline.index");

I get the url, without the port like so:

http://twitter.test/timeline

What is causing this, and is there a fix?

via Chebli Mohamed