FastCGI cache on NGINX causes blank screen in pages

I have the exact same configurations for my other NGINX server with Porto theme and this never happens. Please review my settings and advise:

fastcgi_cache_path /var/cache/nginx/fastcgi_temp/ levels=1:2 keys_zone=WORDPRESS:200m max_size=10g inactive=60m use_temp_path=off;
fastcgi_cache_key "$scheme$request_method$host$request_uri";

server {
	listen 443 ssl ;
	http2 on ;
	listen [::]:443 ssl ;
	server_name jmic.co.kr www.jmic.co.kr; # managed by Certbot
	ssl_certificate /etc/letsencrypt/live/jmic.co.kr/fullchain.pem; # managed by Certbot
	ssl_certificate_key /etc/letsencrypt/live/jmic.co.kr/privkey.pem; # managed by Certbot

	root /var/www/html/;
	index index.php;

	# set max upload size
	client_max_body_size 2G;
	fastcgi_buffers 64 4K;

	access_log /var/log/nginx/wordpress_https_access.log combined;
	error_log /var/log/nginx/wordpress_https_error.log;

	server_tokens off;

 	# START FastCGI
	# POST requests and urls with a query string should always go to PHP
	if ($request_method = POST) {
	    set $skip_cache 1;
	}
	
	if ($request_method = PATCH) {
	set $no_cache 1;
	}
	
	if ($query_string != "") {
	    set $skip_cache 1;
	}   
	
	# Don't cache uris containing the following segments
	if ($request_uri ~* "/wishlist/|/my-cart/|/checkout/|/my-account/|/wp-admin/|/xmlrpc.php|wp-.*.php|^/feed/*|/tag/.*/feed/*|index.php|/.*sitemap.*\.(xml|xsl|html)") {
	    set $skip_cache 1;
	}   
	
	# Don't use the cache for logged in users or recent commenters
	if ($http_cookie ~* "comment_author|wordpress_[a-f0-9]+|wp-postpass|wordpress_no_cache|wordpress_logged_in") {
	    set $skip_cache 1;
	}
	# END FastCGI

	# BEGIN CompressX
	set $ext_avif ".avif";
	if ($http_accept !~* "image/avif") {
	  set $ext_avif "";
	}

	set $ext_webp ".webp";
	if ($http_accept !~* "image/webp") {
	  set $ext_webp "";
	}

	location ~ /wp-content/(?<path>.+)\.(?<ext>jpe?g|png|gif|webp)$ {
	  add_header Vary Accept;
	  add_header Cache-Control "private";
	  expires 365d;
	  try_files
	    /wp-content/compressx-nextgen/$path.$ext$ext_avif
	    /wp-content/compressx-nextgen/$path.$ext$ext_webp
	  $uri = 404;
	}
	# END CompressX

	##
	# BEGIN Nginx Bad Bot Blocker Includes
	# REPO: https://github.com/mitchellkrogza/nginx-ultimate-bad-bot-blocker
	##

	include /etc/nginx/bots.d/ddos.conf; 
 	include /etc/nginx/bots.d/blockbots.conf;
 	# END Nginx Bad Bot Blocker Includes

	include /etc/nginx/site-extras/*.conf;

	location = /favicon.ico {
		log_not_found off;
		access_log off;
	}

	location = /robots.txt {
		allow all;
		log_not_found off;
		access_log off;
	}

	location / {
		try_files $uri $uri/ /index.php?$args ;
	}

	location ~* \.(htaccess|htpasswd) {
		deny all;
	}

	location ~* \.(?:ini|conf|txt)$ {
		deny all;
	}

	location ~ \.php(?:$|/) {
		fastcgi_split_path_info ^(.+\.php)(/.+)$;
		include fastcgi_params;
		fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
		fastcgi_param PATH_INFO $fastcgi_path_info;
		fastcgi_param HTTPS on;
		fastcgi_pass 127.0.0.1:9000;
		fastcgi_read_timeout 60s;

		# START FastCGI configurations
		fastcgi_cache WORDPRESS;		
		fastcgi_cache_valid 200 301 302 60m;
		fastcgi_cache_use_stale error timeout updating invalid_header http_500 http_503;
		fastcgi_cache_min_uses 1;
		fastcgi_cache_lock on;
		fastcgi_cache_bypass $skip_cache;
		fastcgi_no_cache $skip_cache;
		fastcgi_ignore_headers Cache-Control Expires Set-Cookie;
		add_header X-FastCGI-Cache $upstream_cache_status;
		# END FastCGI configurations
	}

	## START SEOPress sitemap location
	location ~ (([^/]*)sitemap(.*)|news|author|video(.*))\.x(m|s)l$ {
		rewrite ^.*/sitemaps\.xml$ /index.php?seopress_sitemap=1 last;
		rewrite ^.*/news.xml$ /index.php?seopress_news=1 last;
		rewrite ^.*/video([0-9]+)?.xml$ /index.php?seopress_video=1&seopress_paged=$1 last;
		rewrite ^.*/author.xml$ /index.php?seopress_author=1 last;
		rewrite ^.*/sitemaps_xsl\.xsl$ /index.php?seopress_sitemap_xsl=1 last;
		rewrite ^.*/sitemaps_video_xsl\.xsl$ /index.php?seopress_sitemap_video_xsl=1 last;
		rewrite ^.*/([^/]+?)-sitemap([0-9]+)?.xml$ /index.php?seopress_cpt=$1&seopress_paged=$2 last;
	}
	## END SEOPress sitemap location

	#START Staging Site SSL location
	location /dev {
		# First attempt to serve request as file, then
		# as directory, then fall back to displaying a 404,
		#try_files $uri $uri/ = 404;
		try_files $uri $uri/ /dev/index.php?$args;
	}
	#END Staging Site SSL location

	# set long EXPIRES header on static assets
	location ~* ^.+\.(?:css|js|eot|otf|ttf|woff|woff2|svg|font.css)$ {
		expires 30d;
		access_log off;
	}

	#CDN CORS policy font fix
	location ~* \.(css|js|eot|otf|ttf|woff|woff2|svg|font.css)$ {
		add_header Access-Control-Allow-Origin *;
	}

	# Rocket-Nginx configuration
	include rocket-nginx/conf.d/default.conf;
}

Hello,

To assist you more effectively, could you please provide additional details regarding the issues you’re experiencing? Including screenshots and a step-by-step guide to reproduce the problem on your website would greatly aid us in diagnosing and resolving the issue.

Best regards,

Pages other than the main page turns blank when FastCGI is enabled with the NGINX configurations above.
I have commented out the configurations to restore the site and it is functioning normally now.

Steps to produce:
1. Uncomment FastCGI settings
2. Reload/restart NGINX server
3. After some time, pages other than the main page / homepage results in blank screen (without any error messages).

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