In my game, for some reason I randomly got off and went back on multiple times without waiting for the w cd which is 10 seconds. I get that if you stay on the champion for more than 10 seconds you can get off and on immediately but I went off, on, off, on a lot of times and when i checked the w description, it even said 0 cd. 
Its 10 seconds at level 1, 5 seconds at level 6, and 0 seconds at level 11.
Playing against that would make my heart sink.
the cool down at lvl 11 is so short it feels like its no cooldown. it scales with lvls without lvling it, so at lvl 1-6 its huge like 10 secs. At six it becomes abit shorter and then at 11 its literally spamable XD it's not a bug it's just yums.
At level 11 there is no CD on her W. Its not a bug. Its intended.
