Witches claws on marijuana plants

A question from a fellow grower:

I took pictures of all my girls to show you, I numbered them with descriptions to follow.
Number 1: is a 18 day old northern lights, fem, while she displays a much healthier countence, she does have some sideways curving leaves. Not to worried for her so far.
Number 2: is a 44 day old super skunk, fem.,I have topped her once, 10 days ago and is thriving and going gang busters. Super healthy so far, and no worries.
Number 3 : is a 43 day old northern lights, fem., I have topped her once, 10 days ago. This is my poor wee deary with whitches claws. I am not sure if you can see the asymmetry and other oddities. Again it seems to display heat stress or nute deficiences, but again all grow situations are the same as my other thriving ladies. Also as a final note on my sad girl. The leaves are not soft and subtle to the touch they feel dry and nearly brittle. I did for a week or two spritzed her many times a day but to no avail. I hope these photos can convey my words and can serve some interest for you. I am gonna stop babbling, I have nearly written you a book, so I will stop. Again I thank you for your interest and support. I look forward to hearing from you and your feelings /opinions.

Looks to me like you have developed a serious PH problem leading to nutrient lock. You must always take care to guard your plants against adverse weather. Peace