Auto Jack - second weed grow

I'm starting to get a little concerned for this young lady. She is a lot smaller than she should be and has very few leaves. I am hoping she doesn't enter flowering phase next week as that will give her some time to grow. Her stem is starting to strengthen though but again I am seeing some kind of deficiency in the leaves. I have made sure not to overwater so it is very confusing. Any help or advice is welcome!