Nginx - PHP file is downloaded instead of 404 error (Piwigo Docker) - php

Question

I will preface this by saying that I almost always use Apache, but am trying Nginx while moving some stuff to a docker container. I am using the Piwigo Docker image from LinuxServer.io located here, and there is an open issue for this pro, but it has yet to be resolved. So, I am hoping that someone here could possibly point me in the right direction. For testing, if anyone is interested, the issue can be seen on a completely clean pull after setup.
Issue: Accessing any page or folder that doesn't exist gives one of two outcomes.
Outcome 1: attempt to access /fakepage.html or /fakepage = PHP file is downloaded instead of served.
Outcome 2: attempt to access /fakepage.php = empty page with "File not found" in the top left.
All configs are shown in the Github link above, but shown here for context.
server {
listen 80 default_server;
listen [::]:80 default_server;
listen 443 ssl http2 default_server;
listen [::]:443 ssl http2 default_server;
server_name _;
set $root /app/www/public;
if (!-d /app/www/public) {
set $root /config/www;
}
root $root;
index index.html index.htm index.php;
location / {
# enable for basic auth
#auth_basic "Restricted";
#auth_basic_user_file /config/nginx/.htpasswd;
try_files $uri $uri/ /index.html /index.php$is_args$args =404;
}
location ~ ^(.+\.php)(.*)$ {
fastcgi_split_path_info ^(.+\.php)(.*)$;
fastcgi_pass 127.0.0.1:9000;
fastcgi_index index.php;
include /etc/nginx/fastcgi_params;
}
# deny access to .htaccess/.htpasswd files
location ~ /\.ht {
deny all;
}
}
When 404 pages should be shown/logged, instead everything is logged as a 200 regardless of file downloaded or "file not found" error shown.
This issue exists on HTTP or HTTPS attempts.
I have tried this in the following Docker Hosts; Rocky 8, Rocky 9, Windows 10, and Ubuntu 22.04
I have changed themes in Piwigo and checked permissions and paths as suggested in other posts.
Here is a sample of what the downloaded php file looks like.
<?php
// +-----------------------------------------------------------------------+
// | This file is part of Piwigo. |
// | |
// | For copyright and license information, please view the COPYING.txt |
// | file that was distributed with this source code. |
// +-----------------------------------------------------------------------+
//--------------------------------------------------------------------- include
define('PHPWG_ROOT_PATH','./');
include_once( PHPWG_ROOT_PATH.'include/common.inc.php' );
include(PHPWG_ROOT_PATH.'include/section_init.inc.php');
// Check Access and exit when user status is not ok
check_status(ACCESS_GUEST);
// access authorization check
if (isset($page['category']))
{
check_restrictions($page['category']['id']);
}
if ($page['start']>0 && $page['start']>=count($page['items']))