Only the moderators of that forum (which is only me, since we're talking about Challenges!) can see which threads are waiting for approval, and smods and higher can see it too. I think I approved it last night though, so you shouldn't be seeing "waiting for approval" anymore. If you are, then it might be a problem that needs to be reported. Like I said, it's a new feature, and with new features, bugs are to be expected. But it should be up normally since I'm pretty sure yours went through approval.