"random" subdomain is shown on invalid subdomain instead of error page

So for example if I enter a non existing qwerty.mydomain.com the content of actual.mydomain.com is shown. I would expect an error page (or redirect to mydomain.com).

Does the try_files clause play a role and is it important at which point it stands (order)?

mydomain conf:

server {
    listen 443 ssl; # managed by Certbot

    listen 8448 ssl http2;

    server_name mydomain.com ;

    root /var/www/mydomain;

    index index.html index.htm index.php index.nginx-debian.html;
        

    ssl_certificate /etc/letsencrypt/live/mydomain.com/fullchain.pem; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/mydomain.com/privkey.pem; # managed by Certbot
    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot
    
    location / {
        include includes/headers.ngx;
        include conf.d/myheaders.conf;

        location ~* "\.(?:css|js)$" {
            include     includes/headers.ngx;
            include     conf.d/myheaders.conf;
            include     includes/.static-files-one-year.ngx;
        }
        location ~* "(?:^/(?:browserconfig|crossdomain)\.xml|\.(?:3gp|cur|eot|gif|htc|ico|jng|jpe?g|mp(?:3|4)|og(?:g|v)|otf|png|svgz?|swf|tiff?|ttc|ttf|txt|wav|web(?:m|p)|woff2?))$" {
            include     includes/headers.ngx;
            include     conf.d/myheaders.conf;
            include     includes/.static-files-one-month.ngx;
        }
        location ~* "\.(?:rss|atom)$" {
            include     includes/headers.ngx;
            include     conf.d/myheaders.conf;
            include     includes/.static-files-one-hour.ngx;
        }
        location ~* "\.(?:manifest|appcache|html?|xml|json)$" {
            add_header Cache-Control "no-cache, must-revalidate";
            include     includes/headers.ngx;
            include     conf.d/myheaders.conf;
            include     includes/.static-files-none.ngx;
        }
        location /_matrix {
            proxy_pass http://127.0.0.1:8008;
            proxy_set_header X-Forwarded-For $remote_addr;
            proxy_set_header X-Forwarded-Proto $scheme;
            proxy_set_header Host $host;
        }
        location /.well-known/matrix/server {
            return 200 '{"m.server": "enterthematrix.mydomain.com:443"}';
            add_header Content-Type application/json;
        }
        location /.well-known/matrix/client {
            return 200 '{"m.homeserver": {"base_url": "https://enterthematrix.mydomain.com"},"m.identity_server": {"base_url": "https://vector.im"}}';
            add_header Content-Type application/json;
            add_header "Access-Control-Allow-Origin" *;
        }

        include /etc/nginx/bots.d/ddos.conf; 
        include /etc/nginx/bots.d/blockbots.conf;

        sub_filter_once off;
        sub_filter ijasdi4ijjiadaioq $request_id;

        try_files $uri $uri/ =404;
    }
}

subdomain conf:

server {
    server_name dimension.mydomain.in.net ;

    root /var/www/mydomain/matrix-dimension;

    index index.html;

    location / {
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_pass http://localhost:8184;
    }

    listen 443 ssl; # managed by Certbot
    ssl_certificate /etc/letsencrypt/live/mydomain.com/fullchain.pem; # managed by Certbot
    ssl_certificate_key /etc/letsencrypt/live/mydomain.com/privkey.pem; # managed by Certbot
    include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
    ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot

    include /etc/nginx/bots.d/ddos.conf; 
    include /etc/nginx/bots.d/blockbots.conf;
}

I have multiple subdomains configured but this is the one shown when an invalid one is used.