The putting grid is never wrong, strictly speaking, because it pulls from the same database of slope values that your putt does.
There are two things that the player needs to take into account. The first, as fmagnets pointed out, is that the grid only gives the "true" break when it is perpendicular to the path of the ball.
The 2nd screenshot shows a 12 foot putt that is crossing 14 or 15 inches of the y axis (vertical lines) of the grid. This is a significant amount - about 10% of the putt's distance. Imagine that there is no break on that putt at all, and think of what would happen to the dots if you were to tilt the surface to give it more straight upslope or downslope. If it's upslope, the dots will fall back from the hole to the left, and they'll run toward the hole to the right if it's a downslope. The steeper the slope, the faster they'll move...but it's still a straight putt.
The second thing to consider is that the grid only tells you the average break across the 2-foot span between y-axis lines. The top screenshot tells what the break is to the left and to the right of the line, but doesn't really say anything about the line itself. That's a great place to use Shiner's suggestion - Chip view - where you can move the grid around for a more accurate reading.
It is frustrating that many holes don't have good camera angles. The new pins on Kia and Congo are especially bad.