I'm a newbie here, this is my first post. I just started my first medical grow and I'm having the same issue as you. I have my soil with 40% coconut coir, 40% Foxfarm Ocean Forest, and 20% Growstone (Supposed to be better than perlite and retain more water and allow more aeration).
I had my fan osculating right up close to the plants and I don't know if that is one of the issues, along with possible over watering. I read that some people say you can get windburn, especially if you have the fan on too high, which I might have considering they are seedlings and in the direct fire of the fan. I only misted the plants a few times throughout the days and gave half ounce of water Every 2 to 3 days. It's day 10 and most of them look good, but a few of them look similar to your plants. Keep us posted on your result, I am thinking I might have overwater them last night. They looked very dry last night, my moisture reader said they were dry so i gave a few of them 1 ounce water, another few plans got 2 ounces, and another few plants got mist. So far none of them have died, so I'm going to let them dry out and keep track of how it affected them.