PHP is executed from the root of the site, and downloaded from the folder. Why?

Question

PHP

I decided to try using puphpet.com to create a vagrant environment immediately on DigitalOcean.com, but I ran into the fact that PHP files from the site root are being executed, that is, site.com/ is being executed, site.com/index.php is also being executed, site.com/phpinfo .php - the source code of the file is downloaded. Next, I uploaded PHPMyAdmin to the /pma/ folder and try to open site.com/pma/ in the browser - it downloads an empty download file.
Piece of Vagrant config

nginx:
    install: '1'
    settings:
        version: present
        default_vhost: 1
        proxy_buffers: '4 256k'
        proxy_buffer_size: 128k
        proxy_connect_timeout: 600s
        proxy_send_timeout: 600s
        proxy_read_timeout: 600s
        names_hash_bucket_size: 128
    upstreams: {  }
    vhosts:
        nxv_b08m6i7th6vi:
            server_name: do-parse-sg.dev
            www_root: /var/www/do-parse-sg.dev/public
            listen_port: '80'
            client_max_body_size: 1m
            ssl: '0'
            locations:
                nxvl_mamkhw4x30hc:
                    www_root: /var/www/do-parse-sg.dev/public
                    location: /
                    autoindex: 'off'
                    internal: 'false'
                    index_files:
                        - index.html
                        - index.php
                        - app.php
                    try_files:
                        - $uri
                        - $uri/
                        - /index.php$is_args$args
                        - /app.php$is_args$args
                    fastcgi: ''
                    fastcgi_index: ''
                    fastcgi_split_path: ''
                    proxy: ''
                    proxy_redirect: ''
                nxvl_a9b530co0qh1:
                    www_root: /var/www/do-parse-sg.dev/public
                    location: '~ ^/(app_dev|config)\.php(/|$)'
                    autoindex: 'off'
                    internal: 'false'
                    try_files:
                        - $uri
                        - $uri/
                        - /app_dev.php$is_args$args
                    fastcgi: '127.0.0.1:9000'
                    fastcgi_index: app_dev.php
                    fastcgi_split_path: '^(.+\.php)(/.*)$'
                    fast_cgi_params_extra:
                        - 'SCRIPT_FILENAME $document_root$fastcgi_script_name'
                        - 'APP_ENV dev'
                    set:
                        - '$path_info $fastcgi_path_info'
                    proxy: ''
                    proxy_redirect: ''
                nxvl_7g5qj8e3fx9d:
                    www_root: /var/www/do-parse-sg.dev/public
                    location: '~ ^/index\.php(/|$)'
                    autoindex: 'off'
                    internal: 'false'
                    try_files:
                        - $uri
                        - $uri/
                        - /index.php$is_args$args
                    fastcgi: '127.0.0.1:9000'
                    fastcgi_index: index.php
                    fastcgi_split_path: '^(.+\.php)(/.*)$'
                    fast_cgi_params_extra:
                        - 'SCRIPT_FILENAME $document_root$fastcgi_script_name'
                    set:
                        - '$path_info $fastcgi_path_info'
                    proxy: ''
                    proxy_redirect: ''
                nxvl_37trhw0b7p16:
                    www_root: /var/www/do-parse-sg.dev/public
                    location: '~ ^/app\.php(/|$)'
                    autoindex: 'off'
                    internal: 'false'
                    try_files:
                        - $uri
                        - $uri/
                        - /app.php$is_args$args
                    fastcgi: '127.0.0.1:9000'
                    fastcgi_index: app.php
                    fastcgi_split_path: '^(.+\.php)(/.*)$'
                    fast_cgi_params_extra:
                        - 'SCRIPT_FILENAME $document_root$fastcgi_script_name'
                        - 'APP_ENV prod'
                    set:
                        - '$path_info $fastcgi_path_info'
                    proxy: ''
                    proxy_redirect: ''
    proxies: {  }

php:
    install: '1'
    settings:
        version: '7.1'
    modules:
        php:
            - cli
            - intl
            - xml
            - gd
            - imagick
            - apcu
            - gearman
            - igbinary
            - libsodium
            - memcache
            - memcached
            - mongodb
            - mysqlnd
            - phalcon
            - redis
            - yaml
        pear: {  }
        pecl: {  }
    ini:
        display_errors: 'On'
        error_reporting: '-1'
        session.save_path: /var/lib/php/session
        date.timezone: UTC
    fpm_ini:
        error_log: /var/log/php-fpm.log
    fpm_pools:
        phpfp_w9qjv2p2d715:
            ini:
                prefix: www
                listen: '127.0.0.1:9000'
                security.limit_extensions: .php
                user: www-user
                group: www-data
    composer: '1'
    composer_home: ''