Soil too hot or on the warm side?

that's just a plant "sleeping" .. they don't put as much energy into turgor pressure when dark or exhausted from too much light. As long as it isn't alldroopy dog for several hours (no idea what a good threshold is) should be fine. If the plant is not receptive to light for long periods of time safe to assume it got too much light before that point. remember just becasue you tried to make things equal does not mean they are... genetics as well as all sorts of variables in the substrate and 2x more so for "organic" prodcuts without guaranteed analysis labels. Can even get a bad batch of supposed inert coco coir... you never know what is different in the substrate.. any number of things could have grown in one and not the other.. or maybe caused by bad watering habits etc... simple bad luck at other times... observe and react - cause and effect. it's good to be consistent, but shit happens nonetheless. if a plant is acting differently... it has a different context or it woldn't be freakin out (not in the topic of this question but in general)