Any chance this isn't budrot?

first signs of necrosis, those single calaxies over ripe mature if mistakes were made during grow, would not panic yet, but i think its anyway chop time, so just watch out a week max and chop her.

Your pictures do not show bud rot, just old dead/dying pre-flowers, the ones that appeared on your plant 2-3 weeks before your plant started flowering properly.

I wouldn't think so... normally bud rot will show up in the buds themselves first... you'll see dead leaves in the middle of a bud when all else looks good around it... and when you pull on the dead leaves, they come out without a problem and reveal more rot underneath. Still, I would keep an eye on this, particularly on the stem... if you see the stem starting to turn brown, it may well be bud rot inside or some other fungus... Good luck!

No it is not a problem, quite often the oldest pre-flowers/primordia growing on the stems go brown and die well before the main flowers ae ripe. This is normal and a non-issue.