Almost always the reason will be that the php.so file is missing but also that php.conf is misconfigured.
In the problem machine it is actually PHP 7 installed so if you reference PHP 5 of course things wil be broken!
Take for example here:
# PHP is an HTML-embedded scripting language which attempts to make it
# easy for developers to write dynamically generated webpages.
LoadModule php7_module modules/libphp7.so
# Cause the PHP interpreter to handle files with a .php extension.
AddHandler php7-script .php
AddType text/html .php
# Add index.php to the list of files that will be served as directory
# Uncomment the following line to allow PHP to pretty-print .phps
# files as PHP source code:
#AddType application/x-httpd-php-source .phps
moodle displays code instead of outputting HTML
cat /etc/httpd/conf.d/php.conf|grep -i addhandler
AddHandler php5-script .php
Fix it and then restart Apache
sed -i s/"php5-script"/"php7-script"/g /etc/httpd/conf.d/php.conf
service httpd restart
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