Your plants are at 14 weeks now? They are pretty much done so I would expect this type of yellowing at this time- harvest by the look of your beautiful buds! Great job and enjoy all of your hard work! 🥂
Leaves yellowing and dying midway through flower towards the end is a pretty normal response. The plant is basically getting ready to die and putting all of its everything into the buds to finish its life cycle like it normally would in nature.