I took a look at the profile and ran the name in my search engine that I use. I can understand why you asked the question. One source popped up that her parents are Edmund de Mortimer, 2nd Baron of Mortimer of Wigmore and Margaret De Mortimer (nee De Fiennes). This source also listed her born 1270.
The other listed her as the child of Hugh De Mortimer and Agatha Mortimer (nee Ferrers). She was listed to be born in 1262.
In this situation, I would put the notations in the biography of Isolde and then disconnect the parents. I would list all sources and the differences that way no research was lost but until a strong conclusion is made, then she is disconnected. Make sure to make note of the disconnected parents wiki id's in the biography. The other thing that can be done is mark the parents "unconfident" and then list why in the biography.
Sometimes, in a situation like this, it takes someone to do the research and leave the message and then do what obviously no one wants to do. The parents can be re-added later if enough viable sources prove they are the correct parents.