Stain on the leaves, pale

I've had exactly the same kind of marking on young leaves and it turns out I had given a little too much fertilizer a little too early... it wasn't much of a problem and once I had backed off on the nutes a bit, the newer leaves were just fine. I think that might be your problem as well - so I'd suggest just back off a little bit on the doseage for the next week - maybe cut it in half for her ... if the others are not showing the same thing, then THEY are able to tolerate that doseage... different plants, even from the same strain and same seed bank, will often require different treatment - identical twins aren't exactly identical! Good luck and enjoy the journey!