I have 13 characters with GM tracking. It's rare that even with GM tracking that the tracking arrow for any one of them points directly at the spot where the target is actually hiding. It is almost always off just a bit. However, this may be happening for me because I don't always have the game window in the legacy client shoved all the way up and over to the left. Perhaps doing that might help?
I can't swear to it and can't find anything to back this up and wasn't around when the skill was added, but I also suspect that the arrow's location generally becomes more precise as your tracking skill increases. I'm also unsure whether your target's hiding or stealthing skill also have a chance to decrease the tracking arrow's precision.