Bug about Spellbook

So, today, 25th of December of 2019, I was playing a game with Pyke and I had the nice idea to use Spellbook as Keyrune, everything went fine until something weird happened, after using my first swapped spell, teleport, and getting my second one ( exhaust ), I couldn't use it. To be more concise, there wasn't a cd timer on the spell, but it was dimmed, as if it were on cd. When I pinged on it, the chat would show that my spell was ready, but even though I was spamming it, it wouldn't go off. I tried to swap more spells and tried to see if the bug would solve itself. The moment I was sure there was a problem was when I swapped for Ghost, but even though I was spamming the key, it wouldn't go off. Desperate, as the game was going really well for me, I had the idea to swap the other spell slot I had and see if I could solve it; magically, the bug was gone. I have some footage if required.