graves guardian angel cosmic insight bug [GAMEPLAY]

when i play graves, sometimes my guardian angel shows it is ready, but when i die it doesn't revive me. this happened to me several times playing with this rune page : glacial augment - perfect timing - magical footware - cosmic insight - nullifying orb - absolute focus. I think that the cooldown shown by the item is counting the 5% on item cooldown of cosmic insight, but the item only works on normal cooldown. As i said this happened to me many times, sometimes even multiple times during a single game, tilting me very hard. I hope this issue will be taken seriously and will be adressed quickly. btw, love the victorious skin.