Bouchard IV, baron de Montmorency - Confusion after merge?

It has been pointed out that the image is of Mathieu II and looking at the dates of two sons called Mathieu and Mathieu II One would expect the younger son to be Mathieu II.

There is obviously an error here somewhere but Were there two of the same name in one generation or have generations been confused since the merge?

Opinions sought please.
Terry Jackson Volunteer Curator

Profiles potentially affected:
Bouchard IV, baron de Montmorency
Mathieu Bouchard Hervé de Montmorency
Bouchard V de Montmorency
Mathieu de Montmorency, seigneur de Marly
//www.geni.com/people/Mathieu-II-Baron-de-Montmorency/6000000002447118571
Mathieu de Montmorency, comte de Ponthieu