Hitting a wall in genealogy is one of most frustrating things that can happen.
One case of it I heard about was told to me by a honest woman with a straight face, I have no reason to doubt it.
Her grandmother had a sister who was never married.
The sister bore 10 children, each by a different father.
The term Wood's Colt applied to all the children.
This occurred in the days before birth certificates.
My favorite scrambling influence is the former practice of naming conventions, such that each generation had members named after grandparents, uncles, aunts, as well as (often) both parents. Not only are there loads of first cousins on both sides with the same few names, there are generally some siblings with exactly the same name because the first carrier of the name died in childhood. :’)