some leaves thin, curled-upward, browning edges

[M.B.A.]

My thermometer records the high and low temperatures (which I reset daily), here they are for the last few days, before and after turning them to 12/12:

83.7 / 79.3
81.7 / 79.3
83.1 / 63.1
73.4 / 69.3

it's currently 79.7

ok, then overwater/over-fert, I also have an electronic Hygro/temp