I try to remodel a asset store asset. I have used the project knife tool and now I try to add new faces to that cut out. I select four vetices and press F but it affects the UV of close by faces, see screenshot
Thats a backface and shouldnt have UV at all.
edit: Ok so I followed this tutorial to get better topology https://www.youtube.com/watch?v=axCYMBRMXo0