Because I have not looked at it, since the last time I tried to fix it.
It is from these changes I made back in May (should be in the notes):
Added AI active sleepers will sometimes be awake and wander (1 in 10).
Added AI wandering sleepers use spawn position as center of wander.
Added sleeper volume trigger type Wander.
Debugging stuff I added. No more detail than that as it would spam the console.