nginx ssl_preread_server_name shows wrong content - nginx

Question

I'm having issues with my nginx configuration, we are using a stream in order to use SSL passthrough, however we plan on having multiple URLs pointed to this nginx and we are wanting to redirect to different load balancers depending on the address
Whats currently happening is..
Both site1.example.com and site2.example.com is showing site1.example.com content
And if site1.example.com load balancer stops working, both site1.example.com and site2.example end up showing site2.example.com content
/etc/nginx/nginx.conf
user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log notice;
pid /var/run/nginx.pid;
events {
worker_connections 1024;
}
http {
include /etc/nginx/mime.types;
default_type application/octet-stream;
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.log main;
sendfile on;
keepalive_timeout 65;
server {
listen 80 default_server;
listen [::]:80 default_server;
server_name _;
return 301 https://$host$request_uri;
}
}
stream {
log_format basic '$remote_addr [$time_local] '
'$protocol $status $bytes_sent $bytes_received '
'$session_time "$upstream_addr" '
'"$upstream_bytes_sent" "$upstream_bytes_received" "$upstream_connect_time"';
access_log /var/log/nginx/access.log basic;
error_log /var/log/nginx/error.log;
map $ssl_preread_server_name $name {
site1.example.com site1_example_com;
site2.example.com site2_example_com;
}
upstream site1_example_com {
server site1.amazonaws.com:443 max_fails=3 fail_timeout=10s;
}
upstream site2_example_com {
server site2.amazonaws.com:443 max_fails=3 fail_timeout=10s;
}
server {
listen 443;
proxy_pass $name;
ssl_preread on;
}
}