whats wrong with this leaf

anyone know what caused this? overwatering?

What are you feeding your plant? What type of lights? And whats the temp in your grow area? Also do you have proper air circulation? Overwatering has signs of leaves curling downward and yellow and fungus growth could appear

...give us a pic of the plant.

Without knowing what your PH, Temp, growing medium, ppms, etc. are, I would throw a guess out of high PH.

If I slack off and my nute barrels get higher pH than they should, then I get a similar leaf twisting. It goes hand in hand with stunted fan leaf development as well. Are any of your fan leaves starting to grow stunted?