[GAMEPLAY] Bug/hack with people flashing multiple times

*riot employee's please read the entire post* [GAMEPLAY] - A bug where flash does not have a cool down.

Recently in a few games I've been seeing people Having flash available again within 30 of flashing initially. On Several occasions this week I've seen this. I know it sounds crazy but i keep immaculate track of enemy flash cooldowns. Just wondering if anyone else has had this problem. And if so, then whats causing it? Is there a new 3rd party flash hack im not aware of? or is it a bug? I wouldn't post this if i wasn't ABSOLUTELY SURE! a flash was cast inside its fair cooldown. To anyone it may concern i have replay footage proving it. Available upon request. Thanks for reading.