Interesting. Do you find that fairly often? I've never seen that before, or even a picture of it for that matter.
I know some things that seem overly uncommon are rather common to me. For instance, in a bed of selects, I might have a half dozen four leafers out of 1000 plants. Today, I dug 50 selects, and had maybe three or four 1 year old plants with double tops. These aren't common, but to me not uncommon. So I'm really curious, because the way you posted, it makes me think this is not uncommon for you and it might be a genetic thing.