Leaf discoloration.

Nothing to worry about, no plant will ever have 100% perfect leaves, 100% of the time. Small blemishes and "funny" leaves will not affect growth or potency or health or anything. It is not caused by anything in particular. Cheers, Organoman.

https://www.bonzaseeds.com/blog/identifying-cannabis-plants-problems/

Your coco needs to stay atop to 100 percent saturated if in straight coco. You can not over water. Plus cal mag is required if not using it.

Little pH fluctuations marks. The wrinkles are the first symptom of overwatering, correct. How to water Cannabis ? Pour enough water to get some drain coming out, it will rinse the excess of NaCl from the pot. Lift the pot, keep the weight in mind and water again when it isn’t that heavy anymore. How to feed Cannabis ? You must need an EC meter, check the ppm amounts of the solution, and check the ppm of the drain, feed again according to ppm levels of the drain to keep the substrate in the right range.

That is nothing. Just a plant mutation. 100% healthy.Gl the rest of the way.

As @gmslave said. Nothing to worry about.

You should try to keep your ph going in down at the 5.7, 5.8 level for veg. Plants grow faster in coco and hydro so first leaves coming out fast and growing fast, sometimes creates a few crinkled leaves some times a spot here and there., no big deal. Cheers