Interesting.
I'm no expert, but the whole point of cloning is that there are no roots to take up moisture, so that job has to be done by the leaves. Thats why humidity needs to be high, and the medium just needs to be comfortably damp. Also, I've never succeeded with clones that small, personally. I finally started succeeding when I started taking clones with around 3 nodes, or about 10-15 cm.