Deploying a localized Laravel app using Dokku

I am using the laravel-localization package to localize my Laravel app. It works perfectly normal on local enviroment (using php artisan serve) and on shared hosting with Apache.

I've just deployed it on a VPS using Dokku, and I am getting 404's on every page that is localized. Other parts of the app work perfectly without issues.

Buildpacks:

https://github.com/heroku/heroku-buildpack-php
https://github.com/heroku/heroku-buildpack-nodejs

Procfile

web: vendor/bin/heroku-php-nginx -C nginx.conf -i php.ini public/
worker: php artisan queue:work --timeout=60 --sleep=3 --tries=3 --queue=high,default

nginx.conf

client_max_body_size 200M;
location / {
    index index.php;
    try_files $uri /index.php$is_args$args;
}

I discussed this already a bit with Dokku maintainers, and it seems that the PHP Buildpack uses the host nginx (nginx.conf.sigil) and the container nginx. Since I'm overwriting the container one in the procfile, I am guessing the issue lies in the host nginx somehow not letting the correct request through?

The .htaccess I deployed with which worked looks like this:

<IfModule mod_rewrite.c>
    <IfModule mod_negotiation.c>
        Options -MultiViews -Indexes
    </IfModule>

    RewriteEngine On

    # Handle Authorization Header
    RewriteCond %{HTTP:Authorization} .
    RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]

    # Handle X-XSRF-Token Header
    RewriteCond %{HTTP:x-xsrf-token} .
    RewriteRule .* - [E=HTTP_X_XSRF_TOKEN:%{HTTP:X-XSRF-Token}]

    # Redirect Trailing Slashes If Not A Folder...
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteCond %{REQUEST_URI} (.+)/$
    RewriteRule ^ %1 [L,R=301]

    # Send Requests To Front Controller...
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteRule ^ index.php [L]
</IfModule>

I'd appreciate any insight about what configuration is preventing the localized stuff to get loaded properly. I've already checked the enviroment variables, config ... and it's all identical on the server - the issue is definitely routing e.g. NGINX.