Hexflash bug?

So last game, around 15 min, I couldn't use my flash anymore. It came from cooldown, but the flash icon just turned grey. When pinging it it said. 'Flash: ready.' But no matter what I tried, I couldn't flash anymore that game. I tried disconnecting, rebinding the key, and closing the entire league client, nothing worked. [sg-ahri-1]

Note: This isn't the first time this happened, the same happened to me a phew months ago. In both games I used hexflash.

Could you please take a look at this bug :)

Love you all