I’m not sure if this applies to the OOB portal but using the Cireson portal, when adding new fields you need to map them to the Target ID of the field you are mapping to. One thing that cought me by surprise was trying to get Requested by User working on the portal for change management but no matter what I did the user was not filled out in the console change request.
There was an out of the box Requested by User field for the Change Class, what was the deal? I decided to dig deeper using SCSM Entity Explorer and discovered that the created by user and requested by user are using the same Target ID. UGH!!
So if you are using the Cireson Portal or find this same issue arising in the OOB portal you will need to create a new RequestedbyUser field and hopefully not have to rewrite a bunch of reports when you finally figure out what happened. Good Luck!