stinging nettle. fun random mutation?

I found one single stem in the nettle patch with 3 leaves whorled per node instead of the usual opposite two. Didn't really realize till I had it in my hand and couldn't find exactly where I cut it from but there were no others. Anyone every seen this? I'll try to root the stem and see if it keeps up this growth habit. Any guesses what's going on with this, random sport mutation or some sort of physiological response?

i see this in sunflower family stuff a fair amount - sunroots and yacon. it doesn’t seem heritable, from what i’ve seen. those shoots that have it seem to have a slight advantage to their neighbors in growth - could well be from having half again as many leaves?