It happens but not as often. Mostly before people convert, they are just deistic/theistic. People tend to believe in a god, but not get caught up in the dogma of Christianity.
Actually, the real issue is "belief". Eventually a lot of people come to realize that believing in things that have no basis in their own experience is a waste of time and energy. And that applies to a lot of the religiosity that people are raised with. So they eventually reject it as pointless and ineffectual.
But some of them eventually will come to realize that belief or unbelief are not the only options. That there is also the option of
faith. And faith is based on hope, not blind pretense (as belief is), so it can have a very real and positive effect in someone's life when acted upon. And so they may choose to pick up their old religion, again. But this time it's on a whole new basis: the basis of faith, not blind belief.
I agree with most of the atheist's complaints about religion as blind belief. But that's always where they stop, because that's what serves their bias against religion. I am not biased against religion as a whole because I understand that as a faith choice, it can be and is very positive and valuable for a great many people. I am only biased against religion as 'belief dogma'. Because I think that's mostly ineffectual, and dishonest.