Hey there,
Your branches are strengthening themselves. It's absolutely normal, we see this quite a bit on area's where you're plant has been "topped" or the new growth has been "pinched". As a plant matures this becomes more recognizable, you're plant is preparing for a heavy load at the top. It's almost like adding additional welds to metal to support more weight. I don't think that's a pre-flower, it looks more like a branch off shoot.
Good luck,
DirtyNerd