Early signs of a deficiency happening.
Also, when a leaf curls or twists, it means your ph is off.
Once your ph is off, certain nutrients will get locked out, giving you more deficiencies.
When the edges of your leaves roll up and your leaves are "tacoing" that means its too hot. Move your light higher or introduce cooler air into your grow. Or get more fans blowing. A fan blowing can reduce temps in that spot up to 25F!!! Insane