Yup, definitely I have some issue with too much lighting. On day 8 the curling continued regardless of the watering from the day before.
Lowered down my lights to 50%, immediately I began to experience problems with the temps diving down, looks like 50% is nowhere enough to heat up the box with outside temps dropping to 2C.
For now resolved with placing a small oil rad near the box. It solved the temp issue but brought in the $$ one. Still fighting on.
On day 9 my leaves are still curled a bit, but the plant looks a bit healthier. Keeping things this way.
Day 10: after all it looks like it was not the led intensity. After 2 days of lighting set to 50% leaves curled further down. I am thinking that It might be underwatering... Hoping that new humidifier will fit the box and will help with constant humidity levels :(
Day 14. New humidifier is in for couple of days, it looks like the whole situation got better. Leaves below are still curled, but I guess it's just going to remain that way.