I know a guy whose mother came from italy to the US when she was young. He went back some Family over there. He was told “you speak Italian well, but you sound like my grandmother”
I work with a younger guy from the south and he definitely has an accent but that could be an anomaly.
One of my Tamilian friends who lived in Delhi all his life went to visit Chennai. He was asked more than once if "he was from Sri Lanka" due to his accent - which was probably not Sri Lankan Tamil accent, but unfamiliar enough to get them thinking.