i know you dont want to hear this again but they are way too dry!!!!!!! you should never let your seedlings dry back so far, their tiny little tap roots will dry out and die back very quickly when there is a lack of moisture. I just saw another post like this one with one strange seedling, that can be one a of a few things. Hot dirt, bad genes, mutated seedlings or bad environment. I have personally let seedlings get too dry and then they do strange things. How to tell if its water? If it doesn't do anything when you go to discard it break open the dirt and investigate the root system, brown and dry are signs of watering issues.. Usually folks stick to smaller pots for smaller plants so that when the plant is ready the dirt is ready. The issue with big pots and small plants is that when the plant needs more water the pot is still easily half saturated, you can use a pump sprayer to lightly mist and keep the tops moist until you get your third and fourth set. Make sure that your watering accordingly, your cups need water every 2-3 days with misting in between. And you pots need a longer dry period but you need to make sure that you keep the soil moist round your seedling during dry periods until a bit more established.
I few things about the environment would help,
What kinda dirt?
What kinda foods/ how often?
What kinda lighting, and how far?
How much water and how often?
Fans?
Humidity?
Whats your water like? PPM/PH tap, well, etc.etc.
