Recently some of the voice lines I used to hear haven’t been triggered as of late 
I’m not sure if this was by design in a recent update but It’s the ones where Vassili says things like “Disarmed, Defused, Dissapointed.” and “I stopped your clock, how’d you like them apples?”
I don’t know what triggered them, but It might’ve been something like getting a headshot on an enemy which killed them, or killing someone when you are on low health
This isn’t obviously only for Vassili but I can’t remember the other mercs lines that well 
I know there have been some changes but we will be looking into the VO very soon.