What kind of deficiency is this?

Could be from your light being too close, 10 inches is really close to the canopy. Light stress will most certainly cause what we are seeing on your plant. You flushed, so any nutrient problems that may have been there should be resolved assuming you are now feeding normal doses at the proper ph. I'd say you have 2-3 weeks left, so I wouldn't start flushing right yet. When you have 7-10 days left just start giving her plain ph'd water, that will allow her to use up any remaining nutrients in the leaves and grow medium. Happy growing.