It seems they didn't make an explanation, how this happened, so here's what I managed to reach out (and touch faith ).
There was a strong backwind on the normal track of 200 m, so they decided to change it to headwind instead. They looked at the track and realized that the first lane is the one, where the track length is the true 400 m. Thus decided to start him from 400 m start mark and finish at 200 m. But of course, no one wanted him to run on the inside track as he has the whole track for himself. So they changed his lane to number 5 - where the fifth hurdle (from 400 m H) is marked exactly in the same place, where 200 m start mark on the first lane. And they used the 400 m start mark from the fifth lane as well. Forgetting that the 400 m from fifth lane equals with 400 m from second after two curves, while in 200 m run they have just one.