[Gameplay][ARAM] Sion's Q/Ult becoming disabled after buying Tiamat/Spirit Visage

After playing as on ARAMs for a while now I notice that when I buy or , Sion's Q/Ult become completely disabled and will not activate no matter how hard I'm mashing Q or R . To be honest, I'm not exactly sure which item triggers this bug, but I'm certain it is one of the two mentioned above. Has anyone else experienced the same issue?