What is up with this kale?

A friend gave us some starts of red russian kale about a month ago. We planted them and they've been doing fine. Today, we noticed these strange spots where there's what looks like a tiny new leaf growing out of the main leaves? There's sort of a puckered spot on the underside. I'm not terribly concerned, mostly just curious what might've caused this. Or if it is normal and just not something I've seen.

That seems pretty normal for the Red Russian kale that we've grown as well.  Probably has something to do with some aspect of the genetics whereby it allows some leaf primordia to initiate leaf growth in unusual places other than at the end of stems.  Although it's not exactly the same thing, other plants like kalanchoe (photo below) can produce new plants at the perimeter of their leaves.  So the plant world has a few oddballs like this.  Should be fine and you should not notice any deleterious effects from it.

Chiming in to confirm, that is what red russian kale looks like.

Thanks John! Plants are such curious beings. I've never grown this variety, so wasn't aware that was typical.
Too bad it doesn't make plantlets like the kalanchoe. That would be some impressive kale.

Before 1990 I had found that Red Russian Kale was not winter hardy in my extreme NW Cascadian location. As told in Carol Deppe's book "Breed Your Own Vegetables", I located every Kale that was similar to the Red Russian Kale I liked growing. I ultimately found about 20 unique kales that were cross compatable and allowed them to cross. I then grew them for several generations also allowing further crosses. Then I selected every year back towards the original Red Russian Kale I had loved while nature selected out the non-hardy ones. The result is a much hardier kale than any I can purchase from any seed company I can find, and I keep trying. I had found my own Red Russian Kale landrace.

Those small leaflets growing from the surface were one of the characteristics I thought were important to re-select for in my Red Russian Kale.