Help - leaf wrinkling and curling

I'm noticing some leaves are wrinkling. Does anyone know what this is a sign of?

Need to provide more info: plant stage, medium, lights, nutrients etc..
First look, very dark and shiny leaves meaning you're feeding her too much nitrogen.
Cut back on the nitrogen cause it will cause even more issues if not corrected.
The deformed leaves are a sign that something is off with your medium, my guess is that she's overwatered.
When you give a plant too much water or too frequent, the leaves get swollen and the cells begin to burst.
More info is needed however, but make sure to ease off on the nitrogen before it locks out other nutrients and distorts the ph in the roots.
Everything is connected, then other deficiencies will appear, some of them look pretty similar and then you're stuck with a neverending headache.

No one likes to think so, but check for broad mites, they also can cause this condition apparently, but I myself have not had them, so just another item to check perhaps.
Good luck
FF

Could be many things. Keep a good grow journal and record EVERYTHING you do. This will help when you have issues. Then you can backtrack to find the issue. Because MANY plant problems are VERY hard to diagnose because so many problems look alike. So the more details you record, the easier it is to eliminate problems and repeat success. Live and learn playa