The same thing happens to me, I always called those preflowers. I think it's the latitude we're at.i don't know if it's just me, but whenever i start plants inside under 18/6 and then put them outside during the spring/summer to veg, they always get calyxes on them. at all the main intersections i get 2 calyxes. they start out looking like little buds, but soon stretch out into long full branches.
i can pollinate them before they stretch out.