Trailing slash/redirection issue NGINX - nginx

Question

I am using Drupal 8 with nginx . I have a multiProject Environment with single domain.
I have 10 Drupal sites. which works as
https://example.com/site1
https://example.com/site2
Each site has its on distinct docker container and everything is running smooth on production. But I noticed A issue with few sites. They give 404 without a trailing slash .Only 4 of them. Rest six automatically appends the slash when I remove them and hit in browser.
The nginx config for all are exactly same.
Here is the nginx config for a site :
server
{
client_max_body_size 128m;
root /var/www/html;
index index.php index.html index.htm;
location /site1 {
try_files $uri/ $uri /site1/index.php?$query_string;
}
error_page 404 /404.html;
error_page 403 /403.html;
# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
location ~ \.php$ {
try_files $uri $uri/ /index.php?q=$uri&$args;
fastcgi_split_path_info ^(.+\.php)(/.+)$;
fastcgi_pass 127.0.0.1:9000;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
include fastcgi_params;
add_header Access-Control-Allow-Origin *;
proxy_set_header Access-Control-Allow-Origin $http_origin;
}
}
I have tried every thing , rewrite, try files and returns.
can any one help.