Gangplank bug/exploit
I was playing a normal game, and we went up against a Gangplank who ulted twice in 20 seconds towards the end of the game. I thought this was suspicious, so I went into replay, and the footage I found can be seen above. The Gangplank reset his ult cooldown 4-5 seconds after using it, and unless I missed some huge rune change, i'm pretty sure that's unintentional. He had 45% CDR and Ultimate Hat, but that only brings his CD down to 65 seconds. The game: http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/2643102924/221282430 Sorry for poor quality in the video, if it's necessary I can upload better quality footage.
Thanks!
Edit: It's been brought to my attention by a helpful comment that this reset happened when GP upgraded his ult. I'm not sure if that's intentional, but I'd figured I'd add this detail.