I happened in my family. One ancestor married his grandfather’s grand daughter. It’s a mess in genealogy.
The country was created by generations who often married cousins of varying distance. It was very common among aristocrats in Virginia (where even first cousin marriage is still legal) and probably other areas.
“ It’s a mess in genealogy”
Genealogy seems to forget about infidelity.
You know, the mailman or the traveling salesman.
My grandparents told the story about Joe. He lived a mile or so away, in visual range. He would get on his tractor and go plow. Shortly after he left a pickup would pull around and park by the house. The truck was there for an hour or two. They all knew who owned the truck.
Old Joes kids never looked like Joe.