A month ago, my family were requested for medical exam forms. After we submitted the forms, yesterday USCIS case status site showed that my wife and I were registered for residents but my son was requested for additional evidence again. Do you know what kind of evidence they ask this time? Is something wrong about my son's medical form? or do they want my son sign some files because he is 18 years old now but he was under 18 when we submitted I-48? Thx