Genealogy is not genealogy if mother's have children in their 50's, have children after the are dead, are 40 years younger or older their their husbands or other impossible feats. If dates don't fit into some realistic format, its just plain wrong to stick them in anyway. They put a search for possible problems option in all genealogy programs for that reason. Is is difficult to get realistic dates before Noah, but unless a genealogy fits into accepted norms you have no genealogy at all. You have a mess. I probably fixed it or deleted it because I do not progress unless it at least fits into the norms.
you might have noticed that the profile for Margaret de Neville has 31 managers. This means that the profile was merged AT LEAST that many times. You can be certain that when that many people enter the same profile, there will be contradictionary sources regarding the dates. So it's less likely that one person entered invalid data, but that in merging conflicting sources ended up in the result.