There are a variety of antirealisms, here I am talking about VA's AND the antirealism explored in the OP. If there is no thing in itself to trigger our fabrication, they any object could be found. The fact that the same or a very similar object is found or the same category of object is found hints that there is some kind of residue that triggers certain associations/patterns in the observer. Otherwise it would be just as likely that we create something else.
There are antirealisms that are agnostic about just what is 'out there'. But that's not VA. He's been clearly that there is nothing there. Also if we create reality, rather than interpret through filters, etc, in an indirect realism, then why would there be any constraints that lead to consistency?
To me it sounds like you are talking realism.That's not the case.
We are getting inputs to our senses and we process those to create a concept of what we believe exists.
And note: I am not dismissing the creating reality idea, in the moment, nor am I saying that VA is wrong about their being no things-in-themselves that are mind-independent, but an explanation for the consistency of responses is needed and I think that's where things get interesting.
And while I haven't done the box experiment, we live informal versions all the time. It's very rare someone walks into what I experienced as a bathroom and they tell me they got some milk from the fridge in there.
So, how does this consistency get made/upheld/maintained between minds, even when those people are experiencing, in different moments, something they are not expecting, and in relation to what other, stranger minds (minds of people we don't know before that) experience.
Again, I think there are answers, even good ones I consider possibly the case, but to me your answer is indirect realism. Which would put you in Atla's camp and not in VA's.
What does the strong metaphysical antirealist say to justify these miracles?