Well, to help determine if it is a LFS bug then you should try seeing if it appears in the replay at the same point. If it doesn't appear again it may have been a hardware glitch, like a problem on the card for a split second, artifact showing up, on it's way to death, etc....
From the angle in the pic it looks like you are indeed watching a replay. So if it happens each time at that spot, then your card heat is ok and not likely the problem.
Try running the replay in Z patch instead of Z10. See if the same graphic bug occurs there.
So there's still more things to try before reporting it as a specific Z10 PATCH bug.