Ubonjoe and all,
I think my friend is in a similar situation. He is American and his wife is Thai but also has a US Passport. Their 7 year old son was born in Thailand and has never been out of the country. He has a US passport. They are planning to take a trip to the US. They are all planning to travel to the US using their American passports so that visas for his wife and son would not be needed. Since their son’s US passport does not have an entry stamp, will they have the same issue as the OP?