Dual Monitor Issue - Game tabs out when I move mouse too far over.

I have this same problem. Started happening to me a few days ago. Rather annoyingly, it seems to do it more often when I'm in the middle of shooting at members of the enemy team.

It seems like I have to back out of the game, then relaunch it a second time for the game to play smoothly without doing this.

It's weird because it never did this when I first started playing ~2 months ago, and I haven't updated any drivers to new versions lately. So, it must be related to some game patch I assume.