[GAMEPLAY] Sion Q and R Problems

When playing as Sion since recently i have encountered a problem with his Q and R abilities not being activatable.

1. The problem has happened around 50% of the games I've played so I presume it is affected by something else.
2. The problem has only occured mid game, i have always been able to use both abilities at the beginning of the game.
3. When activating the R ability after the bug has accured will play the sound found when trying to use an ability when you have no mana.
4. When Sion dies after with the bug you can still use either Q or R to enable his afterlife charge ability. (this does not cure the problem for after death)

Otherwise I haven't found a reason for it's accurance and it has never resolved it's self during a game.