Something is disabling php on my new sites. Help me figure out

Hello,

when i create new sites with my template, the php engine is disabled for that site.
This is what is written on the configuration of the site:
php_admin_value engine Off

To fix that i have to change the directive to ‘1’ (one) instead of ‘Off’, and restart apache. Which is obviously not ideal.

The thing is: i can’t find any configuration in virtualmin AND in the filesystem that could be responsible for this.
Also, i tried to add
php_admin_value engine 1
to the template for the new site, but it still gets disabled by something.

Hint: the problem started to occur when i installed php7.1 alongside php5 (the sites still use php5 unless specified otherwise).

Any ideas?
Thanks