It could also be a iron excess also impairing phosphorous uptake, i see you have some red'ish colours on the stems, this could be caused by too much light, too much cold, or phosphorous deficiency thus my theory.
Consider this only if The8thchevrons answer doesnt fix it because it will most likely do. I'm just coming with this from looking at ur nute shcedule and looking at the plant.
You should also consider if the ph levels are correct.
Stay lit growmie.