This is the first trifoliate sprout I've seen in years. But weirdly, two of the first real leaves grew together as a siamese leaf! The second set of leaves that are coming look like they might be normal. I'm keeping it around for awhile since it seems to be growing just as fast as everyone else... plus it's cool!
I decided to do a bit of reading, and a few places said that Blueberry and mixes were more prone to producing trifoliate seeds. And surprise surprise, this is a Blueberry X God Bud! Notice the very deep purple stem, petiole, and leaf veins. Looks like something is very wrong with it, but it's one of the healthiest seedlings. The 2nd set of leaves are on the way and they look to be normal, including the petiole and vein color. Looks like this one sorted itself out super quick. Hope it's a baby girl.