Whatever the shitta, it is not a matter of minhugim. It is a matter of halacha.
Some davka hold that the kalla should have uncovered hair by her chasana (to show that she is a besulah)
Who are the “some” that “hold” of this “shitta”? According to this shitta, she should need to put the covering on under the chuppa as soon as she becomes an eishes ish to “show” she is now an eishes ish and mechuyuv to cover.