Hi
It's Calcium. IF this was just a nitrogen toxic event, the tips of the leaves would be curling. If a pot leaf were your hand, nitrogen is the bending of your fingers closest to your finger tips, and furthest from the hand. This is a full claw with distortion. It is therefor calcium deficient. The next step, if it is not arrested, will be a loss of luster, and then necrosis, which looks like leaves just drying out, and falling apart. It's a miserable process. Of all my gardening, Sativa dominant strains have been most susceptible. The comments about overwatering are quality(Kudos!), since Calcium gets locked out without water loss. But, the signs of drought are not apparent. From my observation, calcium is the main nutrient served, when letting media dry
.that and Boron.
Peace.