Lighting sounds good. Trying to eliminate the simple things first. It is showing the classic signs of hormone shift that you would see in reveg. The leaf mutations and lateral branching is spot on.
Just reread and caught this is an auto flower. Ruderalis will trigger a hormone shift prematurely if too dry. If it was too dry when sprouting, then watered in good, a hormone shift would be plausible. The leaves are not showing any sign of deficiency or burn so I would just wait it out. Your new growth looks to be normalizing.