I am sharing a first hand story. I know someone who applied for TPS while he was in F1 ( I also applied for TPS but never used it for anything). This guy had come to US for bachelors in around 2009, completed his bachelor in 2014 and joined masters program in 2014 right after his bachelor. He applied for TPS when he was in F1 in 2015. He got the TPS and also he got the advanced parole and traveled to Nepal in around late 2015. He completed his masters in 2016 and joined phd at the same university and went to cananda in 2017 to renew his F1 visa. He told me his F1 visa was very easy to get, they just asked few questions. Also, the so called "status"right after he came from Nepal was "TPS" with underlying F1 according to international office. They told him he would revert back to F1 once TPS is over. I hope this helps. More, I myslef was on F1 but I also applied for TPS in 2015. I have been maintaing F1 and didn't use TPS ead. I traveled to Nepal in 2017 and my visa was expired in 2015 so I went in for renewal. It was a easy task. They didn't even ask me any questions. I hope this info helps!