There is a section on the Wiki page for Odard de Dutton that disputes this parentage:
https://www.wikitree.com/wiki/Cotentin-3
Disproven Existence of Yves St Sauveur
It has become clear that Ivo or Yves St Sauveur de Cotentin, who appears in some popular genealogies[2] never in fact existed, and his existence is considered disproven. As a result, he has been de-linked from the following other profiles, which themselves may need further research:
Parents: He has been shown as the son of Néel (II) de St Sauveur, Vicomte de Cotentin and his wife Adele de Brionne. However, Cawley cites only Leticie, Roger, Guillaume, Gerard, Emma, Bileldis, and Mathilde, but not Yves, as their children. [3]
Marriages. He has been shown as the husband of Emme de Bretagne and Gisele de Beaumont, but as someone who never existed, he cannot have had wives.
Children. He has been shown as the father of the following children, but as someone who never existed, he cannot have children, and therefore the link as parent and child has been broken. Further research regarding the parenthood of these persons is required:
Nigel (Cotentin) de Cotentin, born Cotentin 1043. Niel /Nigel de Cotentin, Lord of Halton, Constable of Chester; [2] Nigel (Cotentin) de Cotentin, born Cotentin 1043 [4] Nigel (B. Halton)[1] Weber reports that Kay Allen referred to Ivo as father (with Emma of Brittany) of Neel/Nigel and Odard [5]Neel (Nigel) Constable of CHESTER , of Halton b: ABT 1043 in Cotentin Penninsula, Manche, Normandy, France (has children) Weber reports that Kay Allen, probably giving the "classic" view of Ivo's issue, states that Ivo was father of Nigel and alleged father of Odard. There are a lot of people that do not accept this due to a lack of evidence.[5]
Odard Cotentin, born Normandy 1046. Odard, 1st Lord of Dutton; [2] Odard Cotentin, born Normandy 1046 [4] Odard (Lord of Dutton)[1] Weber reports that Kay Allen referred to Ivo as father (with Emma of Brittany) of Neel/Nigel and Odard [5]Odard Lord of DUTTON b: ABT 1046 in Cotentin Penninsula, Manche, Normandy, France (has children) Weber reports that Kay Allen, probably giving the "classic" view of Ivo's issue, states that Ivo was father of Nigel and alleged father of Odard. There are a lot of people that do not accept this due to a lack of evidence.[5]
and it goes on to list other children attributed to Ivo
So which is correct?
Thanks