Burnt tips

That doesn't look like burning to me. New growth is always lighter in color until it gets slightly bigger. Usually discoloration happens from the bottom up due to deficiency or toxicity. However the tops can burn if the light is to close to the canopy, you have to much direct wind or if your spraying foliar with the lights on as that creates a prism effect with the liquid. Looking at the pictures looks like healthy growth to me. As always take other people's opinions into account theres much better growers then me here and have fun. Good luck hope you get a great harvest!!