I don’t have a source for this (I heard it in a shiur) but apparently, Rav Moshe Feintein kept a certain minhag (maybe standing for havdalah?) which he felt wasn’t the best halachically, because his father did. He told his sons that he is not transmitting this minhag to them.
There is also an explicit teshuvah in Igros Moshe, as I recall, which says one can switch from Sefard to Ashkenaz (but not vice versa).