[GAMEPLAY] Bug?, bonus speed of Furor boots , Champion : Jhin

[IMG]http://i64.tinypic.com/vncqvn.png[/IMG] [IMG]http://i64.tinypic.com/3yiv6.png[/IMG] [IMG]http://i63.tinypic.com/2u6lqqe.png[/IMG]

normal speed : 425

Furor: + 12%

Speed attacking dragon: 576, which means furor speeded up to +35%

Can anybody explain why? thx