I’m not overly knowledgeable about cars and passed the mechanic’s detailed discussion of my vehicle issues to a friend with more smarts about vehicles than me. Did my friend get a complete and accurate description of the problem from me?
I wasn’t the best conduit for the information.
The same applies to family stories that have been passed down. There could have been details that did not make complete sense to the hearer/reteller of the story and their retelling of that story may have been impacted by that lack of knowledge.
Incorrect details can be unintentional on the part of the teller and may not change the essence of the story. But they can cause our research to go astray if we are unwilling to admit that a relative may have given us some incorrect details.