Plant delayed development

Purple colouration can be hard to guarantee, so you get some that will be purple and some that will not, even with seeds that came from the same packet. The issue with the pistils not turning brown could be due to the fact that you have chosen to go to 12/12, instead of keeping going with 18/6. Going to 12/12 means your plants metabolism has slowed dramatically due to less energy being produced via photosynthesis. Basically your plant is only receiving two thirds the energy compared to when she was under 18/6 and due to the reduction of energy, your plants maturation rate has also reduced. Not sure why you went to 12/12, but I would suggest going back to 18/6 as this will cause your plants to flower and finish maturing a lot sooner than keeping it at 12/12. Since she is an auto, going back to 18/6 should not affect her in any negative way. Hope this helps,.... Organoman.