Any NPC that I put in my dungeon doesn't load.
Well, thats not precisely true.

They don'y load at first but after a seemingly random interval of time (sometimes none show up, sometimes they all start popping in at once) the load exactly where they should be, dead, and flop to the ground. I know this is happening, because I finally caught one doing it.
They do not have start disabled or dead checked, I have no idea why this is happening. It happens to any NPC I put in, ironically unless they already have Start Dead checked.

Has anyone else seen this?

I just realized that, as this is my first time making a big dungeon like this, I don't really know much about NavMeshes. I'm going to go do some reading on them, maybe that is the source of my frustration.

Wow, the wiki article on NavMeshes isn't just incomplete, its practically non-existent.

Yep, making a basic NavMesh fixed it. Sorry to bother everyone.
Now, if only I could get these "thick green lines" they keep talking about...