Accidental Reveggin??

if it is a revege, it's going to be a catasrophe of odd growth, lol.. stems might elongate and you get individual calyxes spread out around it... and then if it starts popping a ton of branches it's going to be a mess of nonsense -- tons of labor to trim little bitty buds with tons of leaves and elongated stems etc... not much you can do. i'd go back to 12/12 immediately unless you want to sepdn 2-3 months waiting for revege to occur and then get it growing normally before you put it back into flower. Anyway, i hope it is a coincidence. you'll see weird leaves with no serations or all of a sudden 2-3 fingers etc... Those leaves at the top ar ea bit concerning.. if oyu see more of those pop all over, it probably re-veged a little. you'll see excessive stem elongation that will make the buds larfy, if so. vege growth normally continues into flower for 3-4 weeks or more, so if you don't see these symptoms, i'd just hold steady - safer at 12/12 if you can give similar DLI as you did over 18h. Hope it is a an autoflower. You'll know better in the next couple weeks.