Burned or genetics?

That purplish tint on the new growth actually looks more like genetics or a natural response to cooler night temperatures rather than light burn. When plants get light stress or "bleaching," the tips usually turn white or a very pale yellow and start to crispy up, but your leaves look relatively healthy in terms of texture. Reducing your PPFD to the 650-700 range is a solid move for this stage anyway, as it prevents unnecessary stress while the buds start to form. If the rest of the plant looks vigorous and the pH is dialed in, I'd say you're just seeing some beautiful colors starting to pop out. Happy Growing Growmie🌱