Maybe too much light and/or heat, not enough fresh air. I have had them contort in the dome before when it is too hot but they come around. If it is rooted too much water and the above. Could just be a bad clone as some have between 50-90% success rates. Some are gonna fail.
Is why I like to do in 4's so one fails I have 3 left to chose from for a mama and first runners.