Auto big Gun (part 2)

This is a normal reaction to the transplantation - in general, I wouldn't worry about the color of those bottom leaves, they're going to die off anyway - but I would worry that you've perhaps stressed her too much as autos don't like to be transplanted or undergo any high stress technique. She needs time to recover and hopefully she will do that before she wants/needs to go into pre-flower. Just give her time.

With your next autoflower grow, germinate the seed in the pot the plant will finish in... autos have their own schedule and the worry is they won't have time to recover before their next step of growth needs to be taken.

Good luck!

The red stems are indicating some stress of some sort.... Really dark leaves will indicate an overload of nitrogen but I'm not seeing that you're giving her much. I think the problem might lie in your EC - it's a bit high for her at this age... notch it down to 0.8 and see how she does... the red stems won't go away so don't look for that... I'd also be adding some calmag to your nutes right about now - this is the moment in a grow when a calcium deficiency can show up...

Good luck!