When a child is added to a person, or a spouse is added, and the wikitree ID is entered at the top of the page AND the parents / spouse is not married, you need to NOT select the Go next to the ID, scroll to the bottom of the page and uncheck the box to state that the parents / spouse is Not married.
If the Parents are married, then the Go button can be used at the top of the profile.
If there are 2 spouses for the parent having the child added, you also should scroll to the bottom to select which spouse is the other parent.