What's the problem? What would you do?

Probably a combination of nutrient imbalance and the plant kinda reaching senescence stage, overall extra pressure so it's depleting those leaves too. As someone else said, a flush, or at least lower strength nutrients (if you're still using) might be a good idea.

Hi mate, she does look a little burnt but the red tips scream zinc deficiency. There seems to be a lot of things going on. If you're so close to harvest is it worth worrying about. good lcuk and happy growing

Offttt yeah dont look that appealing does it now that is so strange that its only effecting the sugars and not the fans I have seen similar things in plants coming upto the end of the grow but usually the fans go first. My best guess would be nute burn or a toxicity of some kind. Give her a flush for a few days see if that has any effect at all. very strange lol Best of luck other than that shes healthy coming upto the end here great job :)