It may possibly be some type of Blight. https://www.zamnesia.com/cannabis-grow-guide/68-cannabis-diseases
It looks like your day time temperatures are cool so your night time temperatures are getting cold. This is leaving a heavy coating of dew on your buds setting up a perfect scenario for mold/rot issues. Don't panic yet another possibility is the wet leaves exposed to strong sunlight may have caused a bit of burn on the tender leaves. With out more information about your grow like watering,nutrients do you spray feed her it's the best educated guess I can make as to a what's going on with your plant. I feel it's odd that your other plants aren't showing the same issues.👍