Why does Nginx return 403 if url repeats http?

Question

Nginx

http://ляляля.ru:8090/play?link=magnet:?xt=urn:btih:e2756abb1a809d0c8fce14db5cbb54acefee45c8&dn=[underver.se].t165055.torrent&tr=udp://tracker.coppersurfer.tk:6969&tr=udp://tracker.leechers-paradise.org:6969&tr=udp://explodie.org:6969&tr=udp://tracker.opentrackr.org:1337&tr=http://retracker.local/announce

on such a link, nginx gives 403 Forbidden. if you remove it at the end &tr=http://retracker.local/announce, then everything is fine.
Why doesn't nginx return a link if the url has one more http:// at the end, and how can I ask it to do so?