Alright, I was mistaken. It happens from time to time.

I had assumed that twitter might have worked with some sort of friend/block list.
And let's say someone not on the mutual friend list had put the community note up, the account that got noted could wipe it by making it reply list only even after the fact. And if they're not on that list, it'd wipe the note.

So it's definitely shenanigans then. That's kinda sad. The people that need it the most get to avoid it.