sion laugh, taunt and joke are bugged not dance

whenever i play sion sometimes he has no audio on laugh, taunt and joke. He moves and dances but dosent say anything no matter how much i press it. This only happends sometimes mostly after start of the game , after i leave fountain and go top or anywhere else and do something a little bit then he bugs out and i cant laugh, joke or taunt. I dont know what makes it happen but i know it happens after you've played a little. It can come back but not always so yeah. Thats the only problem that i've noticed but it ruines a little fun when i want sion to say something.