Agree with Fruitgrower, first sign of nutrient needs. Hard to tell exactly without more info. I’ve unfortunately had to grow in a second floor closet in the summer, tent reaching 90 degrees and didn’t have burn issues. Weedeasy has a great article called nutrient burn that describes the different reasons why leaf tips turn colors. If I knew how to link it I would, but you can search it with the info I gave.
Good luck.