Why is this in the hindsight pool?

noobinall said:

Why is this in the hindsight pool?

I think because it was later confirmed that Aunn was actually a statue before Okina made her into an actual youkai.

Can it really be considered HiH? Most, if not all of the pic in that pool was something the artist did without meaning to; i.e. a coincidence.
Given this one's commentary, it's fairly obvious the artist guessed Aunn's origin (correctly).
Using tropes, this is more of a case of Accidentally Correct Writing.