Shit sounds Bad . What could cause that?
Like others said, lack of airflow, high humidity, and/or rapid changes in humidity causing condensation inside the buds.
The way I look at it, mold spores are everywhere, but they need the right conditions to germinate and infect your plant. For botrytis aka bud rot, that usually means liquid water on the surface of a leaf or bud. So to avoid that, increase your airflow and make sure you don't have pockets of stale air around the big buds where water can condense (the buds and leaves are always transpiring water vapor, you want to remove that water from the surrounding air as quickly as possible), and make sure your humidity stays as constant as possible to avoid dew forming (in my opinion having stable humidity is actually more important than having low humidity).