Enemy casts going off ~0.75 AFTER silence is applied (indicator showing)

Playing a lot of Soraka and Cho this issue keep happening too frequently to ignore, especially looking at the gamebreaking consequences (e.g. enemies still bursting down your team AFTER you applied silence).

This happens so often, you silence an enemy - the silence symbol shows - but the enemy still casts another spell at you.

This bug completely breaks silence as a CC, what is the use of silence when the enemy still gets his casts through and his cooldowns activate anyway? This happens neither with stuns, nor with knockups.

This HAS to be fixed.

(no it's not my ping, constant 22ms)