PH 6.2 is a bit low during flowering. With increase in phosphorus and potassium given during flowering, these blocks calcium and magnesium.
Calcium and magnesium are not mobile. They are stored in leaves and top buds before flowering.
My strategy would be to make sure pH is right for calcium absorption during veg. Then spray calcium and magnesium to leaves and buds during transition.
Since these wonโt move up through roots very much.
After saying all these things, my leaves also yellow and drop.
Finally, i griw for buds and not leaves.