[grim_squeaker_x]

I've seen that happen a few times as well, even before people the NPC smuggling thing, I think created is occasionally called when it's the first time you enter that level since your last connection to the server and if you're then the first person to enter that level.
I'm not sure though.
[Edit]
Or it might occasionally be missing the flag due to packet loss, although you'd have to be pretty lagged to have that happen
[/Edit]