One of my plants has that too. I'm not sure but I'm attributing it to variegation where the leaves have different shades, like a clover leaf. I was concerned at first but now I don't worry about it. The plants appear healthy. Since their genetics have been modified as autos, I'd almost expect something like this. Goes along with my deformed leaves too.
:MmmMedibles..:
Curious...what strain is it?