I too was thinking mold/fungus. The tissue looks necrotic, and the symptoms are localized for now. Are the stems soft where this is occurring? Any kind of smell, other than typical cannabis smell? Like does it smell earthy or sweet, kinda like fermentation (or bacterial infection if you've ever smelled that)?
I had a lower branch sorta similar outdoors fair few years bak but only like the top branch to the right.it was grey black in color and branch actually died i just cut it off and plant was okay.that looks really bad that..
No smell or soft kinda woody feel. Almost looks like it start die. I’m not ruling out mold but would lean towards fungus at this point. Came out a clone dome. Idk what I can spray on stalk