It is mold, sorry.
I would pick a spot somewhere down the branch where there is a break in the buds/completely exposed stem, and cut off everything above that point. You can either trash the whole bud, or try and salvage whatever is not within an inch or so of anything dead/brown/also molded (keep in mind the mold is going to start near the stem for the most part). Edit: if it were me I would just trash the whole bud.
Then I would carefully inspect all the other branches. Usually the first sign of mold inside a bud is a single dead leaf surrounded by healthy green growth, anywhere you see that you more than likely have mold already.
As stated better airflow will definitely help. Also avoiding large temp/humidity swings in general. For example, when the lights turn off, the temp will drop and humidity will rise, which can cause water vapor to condense inside the buds, creating an environment where mold spores can germinate and grow. Better airflow (exhaust and circulation) will help to stabilize the environment so that doesn't happen as readily.
And remove any dead leaves that have a stem going into a bud - it's a lot easier for spores to infect a dead leaf than an alive one.
Good luck!
