sir_isOanswered grow question 4 years ago I don't think that's light, as I grow shit outdoor even in winter, sometimes even without ANY direct light and I don't get shit like that. Your light, temps seem good.
So if I had to guess, internal pressure (hydrogen and oxygen), maybe root related issue. I've somewhat similar results from things fucking up the roots, but I dunno, that looks weird.
If it doesn't rapidly improve, I would seriously consider transplanting that or changing the soil, something like that.