Huge Kayn Bug

So I was playing Kayn in a ranked game, and, long story short, I went bot lane when my essence bar was nearly full, the bot lane consisted of a Volibear (red essence) and a Lucian (blue essence). I ganked them and got essence on both of them, I believe I died in the process, and in the end both of my forms went on cooldown, which is already weird. But as the game went on, I could never switch forms, both forms went int NEGATIVE cooldown.... We lost the game, and that really hindered my performance.

I think I should mention that this is very rare since I have played a good amount of kayn, and have gotten two types of essences at once right before I get to choose a form, and that hasn't happened, I don't know if it has to do with the fact that I died in the process, or if it happened by chance.