Navmeshing Objects - what am I doing wrong?

[pra]

So I have some custom statics, and I have been trying to navmesh them.

Just rightclick->navmesh object, then place some triangles on it.

Then, in-game, I try to order my current follower to walk on it. Or just use Companion Whistle to summon them right onto the object, and see if they will walk off it on their own.

This all works fine when I'm on regular ground, navmeshed using the normal method.

 

It seems to be somewhat random if it works or not. I think it worked once, but usually it doesn't. It doesn't anymore now.

At first I thought my problem was that I didn't finalize the navmesh via the menu (Finalize Cell Nameshes). But now I have no idea.

 

Is there a trick to it? Does the object in question has to have some special KWs/AVs? Must it be workshop-built? (All the objects I'm trying to navmesh will be editor-placed)

 

Or is there a CK bug involved? Do I have to do stuff in a specific order or something?