Hey @vegetato
Looking great! Your plant in the orange pot is suffering from nutrient lock out primarily cal/mag due to pH imbalance. Your pH at the roots is too low you need to flush at the correct pH so your plants can uptake. Plant likes slighty elevated around 6.2 for optimum uptake but swing it through the range as not to starve off other nutes, Your plant is using the manganese from the lower leaves and they will continue to yellow and drop off.
I nursed a plant back with this issue I was diligently feeding it pH correct water but my growing medium lowered the pH at the roots,
Easy to correct if you get on it.