the qc is a bit convoluted. and frankly looks buggy to me.
but...
after *monster_start_go
if (time > self.pausetime)
monster is meant to be walking (assuming its not dead, anyway).
before then, you'll need to check if it has a target, and that its target is a "path_corner" entity. The monster will only patrol/walk if it targets a path_corner. Other entities are ignored (as they are triggered on the monster's death).