could you take a picture or video of the underside of the leaves? Its hard to tell whats going on. The first picture appears to be a kind of infection or mold. The tip of the other picture looks like a burn from nutrients or lights or a combination of the two. If you look closely in the first two pictures. you can see other white formations starting on the leaves. could be water stains but that also means youre not using RO or Distilled water. Just beware of mold and burns. Keep the light at a good distance and dont keep things so moist. Also use clean water and benefical microbes. check your ph religiously and also your ppm. good luck 🙏