Anybody know what causes crumpling?

[JohnnyGrow309]

Growing pink kush. I'm on week 9 of Veggie. Not by choice, I just couldn't start my flower yet. Plant height about 3 feet. Getting about 650-700 ppm per watering. Just recently transplanted to 10 gallon pots. But this crumpling is new on the PK. Not all the plants have it but wanna perfect the environment so if this is caused by something I wanna know. Temperature was at 84 degrees. Set it to 83 degrees today. Humidity averaging around 50-54%.

 

[mysticepipedon]

I believe that leaf sustained a little physical damage when it was small and still growing. Nothing to worry about.