Headlights Kush Auto

Always was curious what will happend to photoperiodic plant if start fucking with light and nigh phases. So after I change it to flower and keep it under 12/12 for 3 weeks , I change the light cycle to 20/4. Basically it's growing with my autoflower😄 Top buds are getting bigger , but they almost like empty inside , very airy and light. Bottom buds kind a undeveloped and very airy. So not sure if it's a strain or my experiment shows results🤓