I said it might be the light because i think the plant, when saturated with light, curls its new leaves upward to reduce light absorption. The upper leaves are a bit crispy too.One thing that makes me think it may not be the light is I think you said youve been dimming them but the lower leafs taco too which unusual. Also that your temps are perfectly fine.
However, I forgot to mention something important. It hasn't even been two weeks since I moved the grow to a much cooler location and under the air conditioning. At one point, it reached 31°C.