Heat and or N def.
So depending upon your conditions, you may or may not need to deal with it.
If it ISN'T heat, if it;s simply N deficiency, and your harvest date is very near, then it isn't something you need to be overly concerned with- you want to see the plant using up its stored nitrogen immediatley prior to harvest.

However I am seeing other stuff, the curling under of the leaves is showing me heat stress and even that the plants could have used larger pots- that's indicitave of being rootbound.