RSS feed Laravel Vapor

I have a simple route that calls a method in a controller to generate an RSS feed of news content.

Works great locally but just will not work in production on Laravel Vapor.

public function __invoke()
    {
        return response()
            ->view('rss', [
                'videos' => Video::all()
            ])
            ->header('Content-Type', 'text/xml');
    }

What's going wrong on Vapor?

I had to tweak the method

public function __invoke()
    {
        $xml_version = '<?xml version="1.0" encoding="UTF-8" ?>';
        return response()
            ->view('sitemap', [
                'news' => News::all(),
                'xml_version' => $xml_version
            ])
            ->withHeaders([
                'X-Vapor-Base64-Encode' => 'true'
            ])
            ->header('Content-Type', 'text/xml');
    }

and then in the view

@php
echo $xml_version;
@endphp
...

and we're good.