My mother's grandmother on her mother's side, who she called Lilly, isnt actually her biological grandmother. Her grandmother died and her grandad married another woman of the same name and they had two more children together. Not a skeleton per se I suppose but I was doing the family tree and discovered it through the civil records and she was surprised when I told her

Also her dad was conceived out of wedlock...his parents married in May and he was born in September. Its highly likely he was early of course and its all above board , but her granny is down as a minor on the marriage cert which makes me think there was a bit of urgency to it