@sun @hakui I noticed the exact same behavior with @lanodan 's account, none of the unlisted posts are visible to me. So, it's not just SPW. I've been noticing it since a few months, but it wasn't so important, so I did not bother looking into until now.
And just to be clear, this doesn't seem to be related to my instance. Unlisted posts from SPW don't show up on lain.com (and some other instances I tried) while being logged out either.