Predender.io docker middleware redirect loop 301 - nginx

Question

I am trying to setup prerender.io for my react platform on AWS ECS along with load balancer, but I keep getting 301 redirect loops, when I visit primary domain.
According to official documentation and github source code, I configured AWS Load balancer accordingly in Load balancer listener rules:
For HTTPS:443, if Host is www2.example.com Forward to ecs_website_container
For HTTPS:443, if Host is example.com OR www.example.com Forward to ecs_prerender_io_container
For HTTP:80, redirect all traffic to https://#{host}:443/#{path}?#{query}
When I check prerender docker logs, every time I visit primary domain example.com I do see some activity in logs, for example:
[13/Aug/2022:18:32:57 +0000] "GET / HTTP/1.1" 301 134 "-" "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/104.0.0.0 Safari/537.36" "12.34.56.789"
So thats the 301 redirect error. It doesnt get to the point of forwarding to www2.example.com.
The source code is exactly same as in official github repository, just the variables are changed obviously. If I go to www2.example.com directly, website works normally, so the problem must be somewhere in the middleware configuration.
I tracked down the redirects and it is as follows (from 1 to 2, from 2 to 3, etc):
1. http://example.com
2. https://example.com:443/
3. https://www.example.com:443/
4. https://www.example.com:443/
5. https://www.example.com:443/
... infinite loop ...
For the sake of clarity, here is default.conf.template nginx configuration which is used:
map $http_user_agent $prerender_ua {
default 0;
"~*Prerender" 0;
"~*googlebot" 1;
"~*yahoo!\ slurp" 1;
"~*bingbot" 1;
"~*yandex" 1;
"~*baiduspider" 1;
"~*facebookexternalhit" 1;
"~*twitterbot" 1;
"~*rogerbot" 1;
"~*linkedinbot" 1;
"~*embedly" 1;
"~*quora\ link\ preview" 1;
"~*showyoubot" 1;
"~*outbrain" 1;
"~*pinterest\/0\." 1;
"~*developers.google.com\/\+\/web\/snippet" 1;
"~*slackbot" 1;
"~*vkshare" 1;
"~*w3c_validator" 1;
"~*redditbot" 1;
"~*applebot" 1;
"~*whatsapp" 1;
"~*flipboard" 1;
"~*tumblr" 1;
"~*bitlybot" 1;
"~*skypeuripreview" 1;
"~*nuzzel" 1;
"~*discordbot" 1;
"~*google\ page\ speed" 1;
"~*qwantify" 1;
"~*pinterestbot" 1;
"~*bitrix\ link\ preview" 1;
"~*xing-contenttabreceiver" 1;
"~*chrome-lighthouse" 1;
"~*telegrambot" 1;
}
map $args $prerender_args {
default $prerender_ua;
"~(^|&)_escaped_fragment_=" 1;
}
map $http_x_prerender $x_prerender {
default $prerender_args;
"1" 0;
}
map $uri $prerender {
default $x_prerender;
"~*\.(js|css|xml|less|png|jpg|jpeg|gif|pdf|doc|txt|ico|rss|zip|mp3|rar|exe|wmv|doc|avi|ppt|mpg|mpeg|tif|wav|mov|psd|ai|xls|mp4|m4a|swf|dat|dmg|iso|flv|m4v|torrent|ttf|woff|svg|eot)" 0;
}
server {
listen 80;
listen [::]:80;
server_name ${PRIMARY_DOMAIN};
location / {
if ($prerender = 1) {
rewrite (.*) /prerenderio last;
}
proxy_set_header Host $SERVER_NAME;
proxy_set_header Connection "";
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_hide_header Cache-Control;
add_header Cache-Control "public,max-age=31536000";
#resolve using Google's DNS server to force DNS resolution and prevent caching of IPs
resolver 8.8.8.8 8.8.4.4;
#setting backend as a variable forces DNS resolution since nginx caches IPs and doesnt play well with load balancing
set $backend "${SECONDARY_DOMAIN}";
rewrite .* $uri break;
proxy_pass http://$backend;
}
location /prerenderio {
if ($prerender = 0) {
return 404;
}
proxy_set_header X-Prerender-Token ${PRERENDER_API_KEY};
proxy_hide_header Cache-Control;
add_header Cache-Control "private,max-age=600,must-revalidate";
#resolve using Google's DNS server to force DNS resolution and prevent caching of IPs
resolver 8.8.8.8 8.8.4.4;
set $prerenderio_host "${PRERENDER_HOST}";
proxy_pass http://$prerenderio_host;
rewrite .* /https://${PRIMARY_DOMAIN}$request_uri break;
}
}
Tried to contact support but no response.