Hello! I’m a United States passport holder currently living in Korea.

I’ve booked a ticket from Seoul to Beijing (71 hours), Beijing to Hong Kong (3 days) and a return flight to Seoul that has a 2 hour layover in Zhengzhou (so Hong Kong—Zhengzhou for 2 hours—back in Seoul). I want to apply for the 72 hour free transit for Beijing, but I want to make sure my short layover on the way back in Zhengzhou doesn’t mess up the visa. Can anyone help me out?