I don't think so since the margins have browned too. How much is she being fed again?Can you also see the yellowing at some of the tips? Could it be nute burn finally showing up from last week?
A K def issue starts at the bottom and works up. It still looks light some sort of heat issue. The damaged leaves will not get better, in fact they will get worse. Keep an eye on the other leaves for the same signs. You may have corrected the issue already.Could it be a Potassium issue?