Alright it was burnt by being slid against an HPS bulb for about a split second.
The reason it is easily seen as light burn and not a deficiency or nute burn is because in nute burn isn't sporadic like that it starts at the tips also it does not get that dark brown without wrinkling or shriveling.
Reason why it is not a deficiency is because in almost all deficiencies it is very uniform and only one part of the plant is affected, either the veins or the out leaf or the tips, also that is growth toward the top so N def can be ruled out. Another point is that parts that are brown are way to brown compared to the rest of the healthy leaf it is part of. If it was a deficiency and it was far eenough along to cause significant cell death to turn the leaf that brown almost the entire leaf would look ill not just the tip of sporadic spots on the leaf