Well i have 24 hr veggies in same closet with 12/12. The plants are 3-4 weeks into flowering, but don't get COMPLETE darkness. But you are just hardly able to make out hairs on buds at 6-8 inches, and when i look at the middle of the plant (without white wall background) i cannot tell that there are individual leaves. How sensitive are plants to this? it is like a bright moonlight i guess. Could these plants become hermaphrodites?
The optimal darkness is Complete Darkness. You can get special lighting that will not disturb the girls if you need to look at them at night. ANY light leaks will cause some amount of stress and can possibly Hermie and plant! I'd try to fix that to get the best conditions for your girls!