magnesium deficiency, most likely.
First, eliminate chance that pH is wreaking havoc. do a slurry or check runoff.
conside what you have fed.. the nutrient content of soil etc...
Epsom salt is a great way to add magnesium. foodgrade stuff is pentahydrate? or whatever the math adds up to 9.8% Mg and 12.9% S
if the soil is known to be hot, it could easily be lockout, but i'd expect to see a smorgasborg of symptoms.. this one looks like Mg-deficiency in a reliable way, but due diligence always necessary.