Severe calcium deficiency..............also starving for potassum and hungry for phosphorous.
Aways show pictures taken in "normal" white light, pictures taken under grow lights are impossible to see correct details in.
Also tip number 1, use light that has a green spectrum as well, the plant may not do much with it, but our eyes can recognize deficiencies earlier with it.
So if you're not doing that yet, then that's a tip from me.
Do you have a pH meter?