Durban Poison Regular

Your diary is incomplete, more info are needed. Things I would check: what’s the distance between plant and lights? Do you check water’s ph? Was your soil fertilized when you bought it? Are you watering with nutes?

Nothing to worry about. It's all about watering. Plant was slightly over watered and roots did get enough oxygen.

lol i know my answer is different too, but something like that happened when I was leaving water on the plants after misting or watering. On a more sensitive plant it happened with just the water even though it had been PH'd, but I found it always happened when water mixed with cal/mag was left on the leaves, resulting in nutrient burn. Now I try to avoid to the leaves or dab at them with a paper towel if I use cal/mag water. Your newer growth looks good, so i don't think it would be a deficiency or light burn. Fungus gnats wouldn't be eating the roots and causing that kind of effect so soon into the plant's life unless the dirt had been recycled. Honestly, my main theory is that water might have been left on the leaves and magnified the light enough to leave unexpected light burn or possibly the nutrient burn. Even one day with the water droplets can be enough to cause noticeable effects, and if your plant was transplanted recently it could make those damaged areas get a little worse while leaving the new growth unaffected - again something I myself did lol. From my experience the leaf twisting could absolutely be a side effect of that as well