Both sides of my family claimed Indian ancestry so either way someone was wrong. I found I have Jewish DNA so maybe it was the Jewish they were trying to hide. It happens that many southern African Americans were told they had native American when really they had Caucasian from slave owners. Maybe the test was wrong in your case, or it didn't pass to her. Maybe they believed there was native American and became interested and studied the language and took on the traditions. I don't know.