I had an auto flower do the same thing. The mold was under the top and working it's way down. It was in the back of a greenhouse, too crowded and humid, I suspect. I moved it outside. I sprayed with anti fungal and it arrested it, but the moldy parts dried and died, yet the rest of the plant continued to flower and mature. I cut away all the moldy branches, (didn't want it to infect the others) but the branches that were unaffected yielded a decent smoke. Not a big bud though. I'd never heard of an AUTOFLOWER before this. I checked these plants daily, and that mold showed up within a day and spread fast.
