Of course he’s natural born - he was born in Texas.
You’re straining at gnats.
The better possibility is the adoption by Soetero and the later use of the Indonesian passport to visit his mother in Pakistan as an adult.
He may well have been born in Texas, but if any other nation holds a claim on his loyalty because of dual citizenship, then I believe the law says he is not “Natural Born” due to his divided loyalties. He is a US citizen at birth, but if he’s also a citizen (subject) of the UK, he has a loyalty problem right there.