Started peppers from seed for the first time ever this year. They germinated just fine and were growing fine under lights for about 2 weeks, then suddenly stopped. I know it probably is too cool in my house for sustained growth, so that is potentially an issue. But the seedling leaves on the peppers (and eggplants) seemed to have cupped/collapsed upward toward the lights instead of branching out. Is this normal? If not what is the issue? Also have zinnia seedlings in a different seed flat under same lights and they seem to be absolutely fine.

Thanks!