I'm not sure why two plants are ok and two plants are not, but I would bring the temps down. I try to keep them around 80 degrees. Have you fertilized the two bad plants? At their size, they look like they don't need feeding yet. I would say that the combo of your powerful lights and the nutes is overkill on those young plants, but I can't justify that being that the other two look fine. Maybe some can handle it better than others? The soil looks the same, did you do anything different to those two? 90 degrees is NOT healthy for them. Bring the temps down to around 78 and see if they get better.