I was thinking about this last night. The confusion with Nute burn might be the type of nute Burn . Nitrogen induced nute burn May show as burnt tips. This is not nitrogen.
I did a little test. I added a teaspoon of tiger bloom to 1/3 of a gallon of water. My PPM’s on a 500 scale went from a base of 210 ppms to 825 ppm’s. I used 50% less tiger bloom than the OP. It was an EC of .6. That would be a lot of bloom food even for an inert media like Coco. Now consider soil already has the full range of bloom nutrients in it. it’s just way too much. Especially at the beginning of flower.
lights being too close would make the situation even worse.