Sion's taunts don't make sound

I play Sion frequently in my games, and I notice that his taunts do not work. Generally this happens after he does a few attack moves, and then his taunts no longer make any sound, but he still does the motions for them, It can either be reproduced by using a skill, or when an all world voice over is made, when one of his skills is pressed, because I don't know which one causes the problem, but one of them does. This issue is extremely frequent, it fixes itself every time he dies, but as soon as a skill is used or maybe a world voice over that everyone can hear is played, his taunts no longer work.