Sorry, not even the dark one: it is actually two chaff seeds still sandwiched together.
I cut a pod off my Karen North several days ago, and you've prompted me to take a look-see....
Definite chaff on left, live embryos on right. I think this is the best seed crop I've ever gotten from Karen North.
Karen North isn't a good parent to learn hybridizing with because it is a triploid, and inherently doesn't "want" to set good seed. And just because there are embryos, doesn't always mean they are good to go. Often, there are complications that arise if the parents are not compatible.
With experience, if you examine them carefully you will start to see that the endosperm (the dark stuff around the embryo) is sometimes not as it should be. In questionable ones, the endosperm area will still seem hollow rather than solid. Solid is always better than hollow, but I can't say definitively that a hollow seed won't live. It doesn't seem like it, though. And even though solid is always better, that still doesn'tnecessarily mean everything is right with the endosperm. The embryo itself can be just a hollow shadow of what it should be too. I don't expect you to be able to discern, but the left group is definitely hollow. The right group not so much. I suspect I will get 3 or 4 seeds to sprout out of this. Whether they continue on is another question.