Is this amended soil? Or you feeding them? This is big info that would help people troubleshoot. Like watering, if it's amended soil then you shouldn't have run off, so that eliminates over watering problem. If it's a properly builts soil than that eliminates your deficiencies.
It doesn't look heat or potassium to me but that's a guess
You could probably figure it out, so more than one plant has curled leaves? Were those Bunched together or mixed with the other ones. Would you say your Technique on watering is pretty much equal on all the pots? Is it the same soil? We're all the ones with curls underneath the same light?
Look at these things and more!
1/3 plants? What does that tell me if I don't have total plant count?
Let's say you have 12, so 4 are bad. Are those four mixed in with the other 8?
If so why would one plant taco but the two beside didn't? Look at the light, is the light directly over the taco plant then it might be light, but that's one thing that we know so far. but let's say it's not say it's over the two that aren't taco well that's weird for the other one to taco when the light is over the other ones that are not?
Got it? Cool rad man
Tell us your findings
Unfortunately no one for sure can say what's going on without knowing all the variables.
Put your hand at the top of the plants, palm facing down, do you feel heat on the back of your hand from the light?