Good luck, Jason. When you say you put it in full sun, do you mean that unrooted cutting, basically just the way it appears in the photo? Won't it get dried out, or is it totally buried in the mix?
I don't remember who it was, but when I was having mold problems with some of my UCD cuttings someone told me to just increase the air circulation around them, and that seemed to help. Recently, I've had good success with putting cuttings straight into a jar of rain water, with just a couple of nodes above the surface, until they show root initials--then they go into a pot, with good air circulation. I think if the roots are growing well before any leaves emerge, they'll be able to handle dry air just fine--but I'd worry about full sun unless there were plenty of good roots.