Strange leaves

Humidity is 70%, watered every 3-5 days, the last time watered 1l 3 days ago to runoff drainage. I also thought about salinity and 3 days ago I spilled an additional 1 liter of water and got 800ml from runoff. I haven’t feed it yet (it’s 14 days old), I use soil cannabigen automix 2.0, it has a lot of nutrients for starters ... I was afraid to give an overdose. Ph water for watering is - 6.5, drainage output - 6.4ph.

These are not clones I can tell. Anyway something is off with the ph or your saturating the medium too much. Either way i'd look towards the soil as the likely culprit if you believed you haven't added too much water. The next culprit would be the soil itself or the Ph of the water your adding to the soil. Lots of folks use like a basic promix which is a nice light acidic soil but there are a kit of variables here... The more I research the more I know how hard it is to pinpoint exactly what is happening.

some twist on new growth, dehyrdated look i guess? is that salinity? don't worry about another strain or even another clone's behaviour.. treat them all mutually exclusively becuase the factors in the soil could make it completely different.. even soil out of the same bag... could be a whole different flora in it by now (microbes good and bad) that naturally occur at all times in different proportions). if feeding regularly from beginning, i'd ease off.. .plenty of room for error in soil, so this would be the safest thing to test first... ensure pH is proper whe you irrigate and feed. pH can cause any and all symptoms and needs to be checked first before adding anything new or chanigng course drastically. i saw this in my first coco grows if not mistaken.. some poorly prepared cheap crap... and i was new to it and did nothgn but use it.. my plants looks a bit like this. Also, in another week it'll be 2x as robust.. it may just go away.. so act conservatively, now. if it worsens, ignore this last tidbit, lol.

Another strain near this one feel great in the same condition... No, fans are pointed under the plant and above them. My light is 50W COB LED now... 50cm above...

Looks to me like either some wind burn or light / heat stress. Is your fan pointed right at your plant? If so point it above the canopy the plant still moves but isn't getting hit directly. Perhaps also move your lights up? In veg with 2 240w from the wall lights I had mine at 30 inches from the canopy. I'd say back yours up a bit! Hope this helps! Happy growing!