Required Fields support needed
Some of the "required fields" underlining changes have been back-ported to 2.3.3, e.g. in system.php and interfaces.php
But the code that supports finding an "*" at the start of the field and converting to an underlined field is not happening (I guess some or all of that has not been backported).
Either backport the underlying infrastructure, or remove the "*" changes.
See issue https://redmine.pfsense.org/issues/7083 for discussion. Looks like this is all being sorted right now.