special episode not showing in "next up"

[TheDreadPirate]

I don't think it is a bug. I'm assuming what you're describing was a design choice to make the specials functionality work with the existing queueing system. It allows specials with "airs before/after" to be queued appropriately, and specials without it to be watched whenever. Without that setting enabled, I don't believe any queueing of specials occurs regardless if they have "airs before/after" set. And that is how it is supposed to be.