a"its a nitrogen deficiency and while a little yellowing very late in flowering is considered ok by many it is not natural for the plant to have yellowing
leaves even at the end of flowering."
You want allot of yellowing towards the end of flowering because it is a sign that the chlorophyll is being used by the plant and if it is still green at the end of flower then the buds have not been able to reach their max potential and you will have a bunch of chlorophyll in the buds and they will take longer to dry and can be more susceptible to mold during the drying process and put off an ammonia smell during the curing process.
2 weeks is a little early, but perhaps when in veg you didn't have enough N. You should feed plants veg nutes up until the first 7 to 10 days of flower, 12-12 because the plant hasn't transitioned over from the flower cycle and is still in veg mode and the veg nutes will help it pack on the needed N for flower. By the end of flower you want about 70 to 85 percent yellowing also known as necrosis.
Adieu