Calcium deficiency is possible, but I don't see much indication of magnesium deficiency, if any. So, there's a possible problem of the plant getting too much magnesium from the
calmag, causing yet another problem.
It doesn't quite look like a calcium deficiency to me, but I can't say that it isn't. How close is this plant to other plants? What's the soil like? Is the plant in a pot or in the ground? Where are the affected leaves on the plant (i.e., high, low or everywhere)? How moist or dry is the soil?