If you think 72 degrees in a veg room is too and burning plants I have a lot of bridges to sell you
if it’s only light burn then why are his top leafs fine? No curling or discoloration. You’re doing a web md right now and saying it matches one symptom so it MUST be that. If the top leaves do it first then it’s definitely light burn, if not then it could be something else. Burning under led looks different than hps as well, that’s why you can’t just look at one light burn picture and say that’s what it is lol. 36 inches in veg is perfect for the
hlg light and shouldn’t burn that much at all. You don’t know if raising the temp could help, saying it flat out won’t is a bit ignorant. Many deficiencies and problems share similar signs, stop trying to web md the OP and try to actually figure out the problem