You woke me up.
So I checked it under mag last night and there's definitely black. It's more evident in hand, but the darkish stripe that you can see in the red in the first pic is actually black, just muted somewhat by lying on top of the thinning-out red and the darkening yellow. Looks like there's black rising up under the yellow . . . Maybe you can see it better in the bottom pic. The seams are dead black, as you see them in the pics.
Kinda odd.