Wedding cake auto Sensible Seeds

I just wanted to do a quick update which is a bit earlier than normal. Bang out of nowhere this bud seems to have rotten and is coated in mould. I've snipped the whole branch as precautions hoping that the rest of the plant isn't affected as other buds look ok...... This is the first time I ever had anything like this. what has caused it all of a sudden is beyond me? I'd say contamination of some sort the way this homegrown tent is set up it can only be from above. Perhaps I've spilt something by accident I don't remember or felt the bud with contaminated hands? The next bud online on the branch doesn't seem affected but trimmed it to be safe! other than this crazy issue, the girl seems healthy. Note: Other growers caution that this came on VERY quickly with the bud looking fine on Sunday, didn't check Monday (today is Tuesday so 48hrs)