Tryndamere's bug

So I just played a game with Tryndamere. The bug I want to report is his ult's cooldown. So when I got 6, the first time I ulted, I saw his cooldown only has 4x sec instead of 1xx sec. And it happened the second time I ulted, still 4x sec cd. However, I remembered pretty clearly that the third time I ulted (I wasn't sure if I was 11lv and upgraded the ult to 2nd level or not), the cooldown goes up to 1xx sec cd (which is the normal cooldown).