Ive had these leave pop up on the 2nd week of flower, I'm growing in a 1.2 x 1.2m tent, 6inch high output extractor, 1 12inch fan, 600w duel spec bulb, 9 plants about 3ft tall in 11ltr pots with a mix of coco, biobiz all mix and perlite. No feed through veg as i kept potting up with new mix. Potted up a week before flower and theyre all doing really well apart from the odd few leaves like in the picture. Any help would be appreciated. Fed twice once at an ec of 1.2 then again just at 1.8 using dutch pro and b, multi total, cannazym and carboload. Temps are fine and no humidity issues.