Let’s assume there’s a kid named John. He was born in California to American parents and is a American citizen by birth.
When he’s ten years old, his parents move to Brazil. They, and young John, become Brazilian citizens and lose their American citizenship.
Fifteen years later, John decides to immigrate to the United States. He comes here as a Brazilian citizen. He likes it here and eventually decides to apply for American citizenship. He passes through whatever procedures exist and becomes an American citizen once again (and loses his Brazilian citizenship).
Is John considered to be a natural born citizen? He was an American citizen at birth and he is one now. But does the gap in his citizenship negate the natural born status?