Blue Mystic Autoflower - need help diagnosing issue

magnesium def is the most common issue other than over fertilizing

micro nutrient issues show at the top of the plant are usually related to ph issue or lock out from over fertilizing

macro nutrient (NPK) issues show at the bottom and work there way up

calcium and magnesium although categorized as micro nutes aren't really micro nutes or macro nutes, theyre kinda in the middle as if they should have a third category
calcium shows at the bottom and middle with rust or red freckles
magnesium ive seen show either top middle or bottom depending on your genetics and grow style

http://rollitup.org/t/chart-for-nutrient-disorder-diagnosis.945735

posted this for you.. it was a bit long to add to your thread so I linked you