HansGoatanswered grow question 9 months ago High, you are so close to harvest that I would not make big changes in the way you grow. It could decrease more yield than that it would be benefitial for your plants.
Your plants are looking great and this small nutrient deficiency could have many reasons. Wrong pH, lack of a nutrient or a excess of nutrient salts builded up inside the medium.
But you are so close to harvest that flushing could harm more then riding it out like you said.
Enjoy your harvest!