hey there that brown spot actually doesnt really look like calcium or magnesium deficiency, for magnesium the burns happen on the edges of the plant and yellowing between the veins but you dont have that at all. For calcium you'll find little ruts sports sometimes clustered but not like that. Actually you have two different kinds of markings, the brown spot and some other spots that are different. The brown spot i think could be from some "random" pH fluctuation which caused some root and leaf stress for example some curling and that brown spot. But the problem is not spreading so it seems that along the way the problem corrected itself. With the other leaf markings, i'm sorry to say but i do think it's pests , the sharp "bite marks" and the way the markings develop some kind of direction on them. So it could be white flies ... actually maybe some day last week or something you probably over or under watered just once and maybe just slightly but it could have created just enough humidity for pH problems and pests to develop. However if you've been following a strict wet dry cycle ever since then it makes sense the soil was able to buffer pH and destroy the white flies eggs just with the dryness . I would absolutely still check the bottoms of the leafs for microscopic black dots just in case these pests have laid eggs or maybe just hibernating. Hope this helps ! π
