Jimmy,
Does it look at all like there is any sort of small nick at the head of that sliver?
I have seen that before where the outer layers are compromised by a small nick or crack in the limb face. If you whack it (I said whack it.)....if you whack it against something small and sharp (Treestep, someone elses cam edge, bowhook etc)without realizing it you can get deep enough to affect the glass itself and it can feather up.
It might be hard to tell now because usually the glass will lift in the shape and width of the nick itself.
Not saying that's the case but that's the most common reason for that type of limb damage that I am aware of. The true CRACKS that you can see in glass limbs that go deep into the limb body are many times due to improper pressing.