Do you take ph readings? Incorrect ph can lockout nutes.
Seems like its running low on phosphorous but then again, i dont know what ph is the water they are getting so it could be a ph induced phosphorous lockout.
Check ur ph, if u dont usually then invest in a ph reader at least, not even getting into ppm as a ph reader should be enough if u don't abuse the nutes.
Shoot me a dm if you need anything or if dms are stilk bugging you can drop a comment on my profile to get my attention.
P.s. when using nutrients start off at ⅛ strenght, then ¼ then ½ and then u reach full dose, and don't add nutes in every watering, keeping a plain water inbetween feedings is a good plan for soil growers.