don't assume I kno what I'm on about.. I just make it sound good hahah
errr, I've seen that before some years back.. I wouldn't say its nutrient straight away I'd say temperature. But we can diagnose;

What is the concentration of your nutrient feed in the system? Is it a full dose as prescribed on the container?

What is the distance of your light from the tops of the plants?

If I remember, the very last time I saw light green curling leaves similar to that, but worse, was when I drowned the roots using NFT. Is your NFT system duct taped to the max not allowing oxygen to the cubes?

Could be lacking in nitrogen? errrrr... Describe what you have done up to this stage, then we can all offer assistance!