What’s wrong here guys

I never worry to my about the 1st couple leaves sometimes they can be a bit funny for numerous reasons check the new growth if the problem is still there investigate further

Young plants that are in caked watered logged coco suffer with lack of oxygen at the roots. You have no perlite in your soil. You can keep coco wet once you have the root structure to acomodate the water, but if you have young plants with a small root mass, you can over water and kill them in Coco. I can speak from personal experience. You can also create root rot situation in wet coco when they are young. You'd have to have 100% humidity in your space to have any kind of effect on the plants. Cannabis easily grows and thrives in a 80% humid environment, and i doubt you have RH higher than that. The wavy leaves are an indication of pH fluctuations. Allow your coco to dry out between waterings and they will bounce back, if you've not created the onset of root rot. I grow in coco and i never let my plants stay in soaked coco. I always allow a dry out before each watering. Never had an issue, and i yield the same as someone that keeps it soaked. Difference being i use less water and nutrients to achieve the same result as someone using double the materials

Being in coco and always being wet is how it is suppose to be done. I think it might be your humidity is too high. So it's not overwatering. But never let them sit in run off.

Totally overwatered, in the last pic you can see the green mold all around the soil, water less or let them dry more time.

Usually it happens in dry environment, in your case it could be lost of moisture on growth tips (whatever the reason).

Humidity too high for them maybe? I’m completely guessing here