Sion VO broken

I just tried out Sion in a custom bot game, and for a while he would speak his voice lines to the J4 I placed in the mid lane. But ever since using my first ult cast, his VO was not saying anything (movement, attacking, recalling, shopping, joking, taunting, laughing, etc.) but it would work when I used abilities like Q, W and E. Only at random was I able to hear anything, and I had to cancel purchases and repurchase just to hear his unique VO for particular items.