Sugar leaves burnt/dry spots.

You can try giving her a good flush. I had something similar happen a while back and I wasn't sure if it was a lack of something or too much so I gave it a good flush and afterwards I watered it with only the additive,"recharge". It actually did help my plant and I was able to return to regular feeding schedule the following week plus I went ahead and picked up most of the old leaves that were affected so my plant could focus her energy on the buds. Don't know if this will help you but I wish you all the luck and hope you Great Harvest ♡ Happy Growing☆☆

Hey Growmie, This is perfectly normal since your near harvest its the plants way of showing its near the end. Hopefully I answered your question and remember Happy Growing and Free your mind one puff at a time.

The plant is near the end of its cycle and starting to die, nothing you do will change that.

Up the phosphorus and try not to worry. Leaves will start dying at this stage, although not usually so high up.