>>211922170Bordergore was common back then. In fact many modern maps simplify the borders of medieval states.
Here is for example a map of the County of Namur. That's pretty bordergore and even this is a bit simplified.
I suppose it's because medieval rulers didn't have a map as precise as ours in mind when thinking about their territory. It was more a king ruling over dukes ruling over counts ruling over smaller nobles who managed some peasants, and someone could without problem have a vassal whose territory wasn't contiguous to his other vassal's territory.