Not heat damage, but it's more you're force feeding it more food "photons" than it can take in. Over eating is not good for any lifeform. If you've had your light this high through veg, your problems will be exacerbated from an under developed root system by the time you hit mid stretch in flower. In veg you should be at 350 ppfd or less.would you expand on that please?
LED light and under 700 ppfd in flower and no heat to speak of from the diodes, i don't understand how that could burn the plant.
all the leaves top to bottom look like this.