Legality of apartment fees?

2 days before I'm due to move into my new apartment, they want to charge my roommate a security deposit. The manager says it's because she has not worked at the same place for 12 months consecutively. However, the contract says that she needs to work 12 months, but nowhere does it say consecutively at the same place. She has worked more than 12 months, but between 2 jobs because she moved. Also, in the contract it says that it would be okay for her to not work 12 months if I meet the income criteria, which I do. So is it legal for an apartment complex to charge fees even though my roommate and I meet the criteria?