We recently had a problem with parking domains after installing CSF. We do not serve DNS so we disabled the DNS service. We found that we could no longer park domains unless we did it through WHM which means more support since our users can't do it through cPanel.

so we opened a ticket and it was recommended to us that:
login to WHM, and navigate to Tweak Settings, and enable the following;

"Allow Creation of Parked/Addon Domains that resolve to other servers "
Developers please see ticket: 627730

I suggest that if we are disabling local DNS this tweak setting should be set automatically. Any other gotcha scenarios should be planned out and set automatically to reduce support requests and ease for cPanel users.

Thank you for your consideration.