What this means?

nitrogen and calcium but if soil reminds just overwatering and pots (rich in food) ph swing. triple check ph in and water only when pots are light if its soil in coco - only ph, plant cant uptake, but you feed too heavy too. some plant are light feeders. direct wind or coldest corner can play a bit and look similar, but i would bet on my theory

You're plants are doing fine, you might have had a small issue with PH fluctuations but other then that you're doing fine, make sure your VPD is on point and keep doing what you're

I think you got some pH issues goin on there. And perhaps some suffocating roots. The back right corner plant looks ok but the droopy wrinkled leaves suggest the issues mentioned. Keep your pH 6.2 going in, always. And water only when the pots feel light. If they feel heavy, turn around and fuck off. :)

Damaged caused by the over feeding 2 weeks ago.

Do you have a fan moving air in your tent as well as moving the plants

erm it looks to be an imbalance in your ph I dont think its a toxcity unless you know you have overfed. with high huditiy you can get leaves canoing. 4 plants in that sized tent will create alot of humidity. this might be the reason make sure you have a good air echange in there buddy :)