While that's certainly a possability, if you examine the soil carefully in the pics, it has several dry spots in the top layer. If it were mine, and I've certainly had issue's just like that before, I'd get those babies cooled down. Those symptoms are also a sure sign to me that my soil is way hot, especially for seedlings. If it were mine, I'd be flushing that soil. Since it was a very recent transplant, you could also repot them into ...say a
Roots Organics Original, or a Fox Farms
Happy Frog. Both of those are 'cooler' formulated soils.
Hope that helps,
N2
What soil is that planted in?