shein, and that halachic basis was…… They didn’t care.
My point being is that people constantly say you can’t change a minhag because of mesorah , your father did it this way etc when in fact, as the Chassidim did, if you are going to change anyway, you’ll find a basis ir it
At some point in time, whether it be gabrochts or any minhag, someone in the past changed their minhag to adopt their current one. They aren’t set in stone, or at least shouldn’t be