I am petitioning for my parents. Last year, they were here on visitor's visa, which was originally issued for 6 months. They applied for an extension at 5th month, but they didn't get any response from USCIS until the 10th month with an extension denial. In the denial letter, USCIS asks my parents to leave the country within 30 days and they did. I am wondering if this is a serious issue during their interview. thanks.