Please can you let me know that why Expires header are not updated instantly with current date? This showing Expires: Thu, 19 Nov 1981

I am using this code in .htaccess

Code:
RewriteEngine On
# Redirect www to non-www from HTTP to HTTPS
RewriteCond %{HTTPS} off [OR]
RewriteCond %{HTTP_HOST} ^www\. [NC]
RewriteCond %{HTTP_HOST} ^(?:www\.)?(.+)$ [NC]
RewriteRule ^ https://%1%{REQUEST_URI} [L,NE,R=301]
# HTTP Authentication with cgi/fastCGI
RewriteCond %{HTTP:Authorization} .+
RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
# AutoSSL validation required HTTP redirects
RewriteCond %{REQUEST_URI} !^/[0-9]+\..+\.cpaneldcv$
RewriteCond %{REQUEST_URI} !^/\.well-known/pki-validation/[A-F0-9]{32}\.txt(?:\ Comodo\ DCV)?$
# SVG Support
RewriteRule ^data/svg/([^/]+)/([^/]+)/([^/]+)/([^\.]+).svg$ svg.php?svg=$4&s=$1&l=$2&d=$3 [B,NC,L,QSA]
# Prevent viewing of .htaccess file
<Files .htaccess>
order allow,deny
deny from all
</Files>
# Block An IP Address
Order Allow,Deny
Allow from all
Deny from 182.160.128.0/18
# Mod_security can interfere with uploading of content such as attachments. If you
# cannot attach files, remove the "#" from the lines below.
<IfModule mod_security.c>
SecFilterEngine Off
SecFilterScanPOST Off
</IfModule>
ErrorDocument 401 default
ErrorDocument 403 default
ErrorDocument 404 default
ErrorDocument 405 default
ErrorDocument 406 default
ErrorDocument 500 default
ErrorDocument 501 default
ErrorDocument 503 default
<IfModule mod_rewrite.c>
RewriteEngine On
# If you are having problems with the rewrite rules, remove the "#" from the
# line that begins "RewriteBase" below. You will also have to change the path
# of the rewrite to reflect the path to your XenForo installation.
#RewriteBase /xenforo
# This line may be needed to enable WebDAV editing with PHP as a CGI.
#RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -l [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^.*$ - [NC,L]
RewriteRule ^(data/|js/|styles/|install/|favicon\.ico|crossdomain\.xml|robots\.txt) - [NC,L]
RewriteRule ^.*$ index.php [NC,L]
</IfModule>
AuthName "public_html"
AuthUserFile "/home/nadda/.htpasswds/public_html/passwd"
# BEGIN cPanel-generated php ini directives, do not edit
# Manual editing of this file may result in unexpected behavior.
# To make changes to this file, use the cPanel MultiPHP INI Editor (Home >> Software >> MultiPHP INI Editor)
# For more information, read our documentation (https://go.cpanel.net/EA4ModifyINI)
<IfModule php7_module>
php_flag display_errors Off
php_value max_execution_time 600
php_value max_input_time 3600
php_value max_input_vars 100000
php_value memory_limit 1024M
php_value post_max_size 32M
php_value session.gc_maxlifetime 1440
php_value session.save_path "/var/cpanel/php/sessions/ea-php73"
php_value upload_max_filesize 16M
php_flag zlib.output_compression Off
</IfModule>
<IfModule lsapi_module>
php_flag display_errors Off
php_value max_execution_time 600
php_value max_input_time 3600
php_value max_input_vars 100000
php_value memory_limit 1024M
php_value post_max_size 32M
php_value session.gc_maxlifetime 1440
php_value session.save_path "/var/cpanel/php/sessions/ea-php73"
php_value upload_max_filesize 16M
php_flag zlib.output_compression Off
</IfModule>
# END cPanel-generated php ini directives, do not edit
RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !^http://mysite.com/.*$ [NC]
RewriteCond %{HTTP_REFERER} !^http://mysite.com$ [NC]
RewriteCond %{HTTP_REFERER} !^http://mysite.net/.*$ [NC]
RewriteCond %{HTTP_REFERER} !^http://mysite.net$ [NC]
RewriteCond %{HTTP_REFERER} !^http://www.mysite.com/.*$ [NC]
RewriteCond %{HTTP_REFERER} !^http://www.mysite.com$ [NC]
RewriteCond %{HTTP_REFERER} !^http://www.mysite.net/.*$ [NC]
RewriteCond %{HTTP_REFERER} !^http://www.mysite.net$ [NC]
RewriteCond %{HTTP_REFERER} !^https://mysite.com/.*$ [NC]
RewriteCond %{HTTP_REFERER} !^https://mysite.com$ [NC]
RewriteCond %{HTTP_REFERER} !^https://mysite.net/.*$ [NC]
RewriteCond %{HTTP_REFERER} !^https://mysite.net$ [NC]
RewriteCond %{HTTP_REFERER} !^https://www.mysite.com/.*$ [NC]
RewriteCond %{HTTP_REFERER} !^https://www.mysite.com$ [NC]
RewriteCond %{HTTP_REFERER} !^https://www.mysite.net/.*$ [NC]
RewriteCond %{HTTP_REFERER} !^https://www.mysite.net$ [NC]
RewriteCond %{HTTP_REFERER} !^http://image.mysite.com/.*$ [NC]
RewriteCond %{HTTP_REFERER} !^http://image.mysite.com$ [NC]
RewriteCond %{HTTP_REFERER} !^http://www.image.mysite.com/.*$ [NC]
RewriteCond %{HTTP_REFERER} !^http://www.image.mysite.com$ [NC]
RewriteCond %{HTTP_REFERER} !^https://image.mysite.com/.*$ [NC]
RewriteCond %{HTTP_REFERER} !^https://image.mysite.com$ [NC]
RewriteCond %{HTTP_REFERER} !^https://www.image.mysite.com/.*$ [NC]
RewriteCond %{HTTP_REFERER} !^https://www.image.mysite.com$ [NC]
RewriteRule .*\.(jpg|jpeg|gif|png|bmp)$ - [F,NC]
# php -- BEGIN cPanel-generated handler, do not edit
# Set the “ea-php73” package as the default “PHP” programming language.
<IfModule mime_module>
AddHandler application/x-httpd-ea-php73 .php .php7 .phtml
</IfModule>
# php -- END cPanel-generated handler, do not edit