Burned tips and white spots

That doesn't look like a nutrient issue to me. It's either a tiny catterpillar or most likely the leaves got wet and sun on them and burned like a magnifying glass or there was feed spilled and as the water evaporates it gets more concentrated and burns. The burnt tips are only on one leaf, so I would guess that is also damage from something else, maybe got too hot at some point. Not sure what has caused it, but doesn't look like nute burn.