Hello DeeCee, your girls are still looking good.
I see your problem, its sucking the nitrogen out of its leaves.
That said it could be different things, not enough nutes at this stage.
Maybe its not getting enough nutes or not consistent.
Do not let your medium dry out completly (its bad for your girl and her roots), put your finger top in your medium when its a bit moist u can feed her again, if its really wet wait another day.
Also i see your humidity is a little bit on the low side, it should be more between 65% and 55% i would recommend a foliar spray with silica or give silica with the regular feeding.
I think thats about it and if you do something now they will bounce back up.
Hope this was an helpfull answer my friend, if so give the answer a like.
Keep on growing. Peace 👍