It's very common for kids raised in conservative religion to become 18 and seemingly abandon that lifestyle, acting the opposite, experiencing all the things they were denied, and becoming a wild child, so to speak. Only to revert back to their original ingrained ways once they become a little older.
It makes me think of Amish communities and rumspringa where children that reach adulthood get a stretch of time to live free of the community rules and see whats it like to live as an English person.
Most come back to the life they had always known, some don't. Christian Fundies are the same.