There are two girls in this state, one more critical than the other, they have the same watering schedule as their sisters, I think it’s the seed/genetics that came faulty.
Previous message should say PH Test the medium. And also this could be showing signs of being root bound or root rot. I hope you get it fixed! Good luck!
https://www.ilovegrowingmarijuana.com/marijuana-diseases-fusarium/
Check the main stalk and maybe oh test the medium? Worst case it could be Fusarium. Best case it's just genetic.