One thing you may want to keep in mind is that as of Geneva, ServiceNow uses anonymous function calls and no longer uses the onBefore() onDisplay() or onAfter() functions. I have seen that the syntax of the functions that I used in Fuji, no longer work. Here is your code using the anonymous function syntax:

(function executeRule(current, previous /*null when async*/) {

//Populate IP Address from network task from Hardware Request   

       var pc = new GlideRecord('sc_task');   

       pc.addQuery('request_item.request', current.request_item.request);   

       pc.addQuery('assignment_group', '287ebd7da9fe198100f92cc8d1d2154e'); //network group   

       pc.addNotNullQuery('u_ip_address');   

       pc.query();   

       if(pc.next()){   

               current.u_ip_address = pc.u_ip_address;   

       }

})(current, previous);