Ah, yes. GTA V appears to use a very odd method of hooking the keyboard, which actually causes system-wide issues on my machine; If I have it running, my keyboard input into other applications is slowed down immensely at times.
I also have to start VoiceAttack after GTA V, or VoiceAttack's keyboard hook won't work(and randomly stops working, probably after tabbing out of the game a few times).
This is a GTA V issue in my opinion, not much Gary can do about Rockstar's poor porting work.