proxy reverso nginx servindo site errado

Question

Tenho o nginx rodando no Debian 12 como proxy reverso -com terminação SSL- para vários sites. Recentemente notei que não consigo mais adicionar mais hosts devido a esse comportamento estranho. Habilitei o site padrão, mas, sistematicamente, quando apontei o navegador para sub-xx.domain.com fui redirecionado para a.domain.com. No entanto, todos os sites de a a w estão funcionando conforme o esperado. Se a solicitação for HTTP, o navegador avisa sobre a insegurança do site e é redirecionado para d.domain.com. Quando você solicita explicitamente, o HTTPS é redirecionado para a.domain.com conforme mencionado. Os logs de xx.domain.com não têm rastro e, apenas se a solicitação for HTTPS, os de a.domain.com têm isso

192.168.9.1 - - [19/Jan/2024:16:55:04 -0300] "GET /img/logo.gif HTTP/2.0" 200 3418 "https://xx.domain.com/css/login>

xx.conf

pstream xx {
   server 192.168.8.86;
   keepalive 32;
}

server {
    listen 80;
    server_name xx.domain.com;

    include /etc/nginx/snippets/location-letsencrypt.conf;

#    return 301 https://$server_name$request_uri;

#}

#server {
#    listen 443 ssl http2;

#    server_name test.xx.domain.com;
    
#    include /etc/nginx/snippets/location-letsencrypt.conf;
#    include /etc/nginx/snippets/ssl-params.conf;

#    ssl_certificate /etc/letsencrypt/live/xx.domain.com/fullchain.pem;
#    ssl_certificate_key /etc/letsencrypt/live/xx.domain.com/privkey.pem;

    location / {
       include /etc/nginx/snippets/proxy.conf;

       proxy_pass http://test_xx/;
    }

    access_log /var/log/nginx/xx.domain.com/access.log;
    error_log /var/log/nginx/xx.domain.com/error.log;

}

aa.conf

upstream yy {
   server 192.168.8.81;
   keepalive 32;
}

server {
    listen 80;
    server_name yy.domain.com;

    include /etc/nginx/snippets/location-letsencrypt.conf;

#    return 301 https://$server_name$request_uri;

#}

#server {
#    listen 443 ssl http2;

#    server_name yy.domain.com;
    
#    include /etc/nginx/snippets/location-letsencrypt.conf;
#    include /etc/nginx/snippets/ssl-params.conf;

#    ssl_certificate /etc/letsencrypt/live/yy.domain.com/fullchain.pem;
#    ssl_certificate_key /etc/letsencrypt/live/yy.domain.com/privkey.pem;

    location / {
       proxy_http_version 1.1;
       proxy_set_header Upgrade $http_upgrade;
       proxy_set_header Connection 'upgrade';

       proxy_set_header X-Real-IP $remote_addr;
       proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
       proxy_set_header X-Forwarded-Proto $scheme;
       proxy_cache_bypass $http_upgrade;
       proxy_pass_request_headers   on;
       proxy_pass http://yy/;
  }

    access_log /var/log/nginx/yy.domain.com/access.log;
    error_log /var/log/nginx/yy.domain.com/error.log;

}

nginx.conf

user www-data;
worker_processes auto;
worker_rlimit_nofile 100000;
pid /run/nginx.pid;
include /etc/nginx/modules-enabled/*.conf;

events {
    worker_connections 10240;
    multi_accept on;
}

http {

    ##
    # Basic Settings
    ##

    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
    keepalive_timeout 65;
    types_hash_max_size 2048;
    server_tokens off;

    server_names_hash_bucket_size 64;
    # server_name_in_redirect off;

    include /etc/nginx/mime.types;
    default_type application/octet-stream;

    ##
    # To avoid error 413
    client_max_body_size 192M;


    ##
    # Logging Settings
    ##

    access_log /var/log/nginx/access.log;
    error_log /var/log/nginx/error.log debug;

    log_format  main  '$remote_addr - $remote_user [$time_local] 
                             "$request" ' '$status $body_bytes_sent 
                             "$http_referer" ' '"$http_user_agent"
                             "$http_x_forwarded_for"';

    #access_log /var/log/nginx/access-special.log combined;

    ##
    # Gzip Settings
    ##

    gzip on;

    ##
    # Virtual Host Configs
    ##

    include /etc/nginx/conf.d/*.conf;
    include /etc/nginx/sites-enabled/*;
}

localização-letsencrypt.conf

location ^~ /.well-known/acme-challenge/ {
    allow all;
    default_type "text/plain";
    root /var/www/le_root;
}

location = /.well-known/acme-challenge/ {
    return 404;
}