You didn't happen to set an allowed area for your colonists that excludes the trap zone, did you? They can't go retrieve the kill if they aren't allowed in that area.
Other than that, I'd check to make sure that the butcher bill allows for the specific type of creature that was killed by the trap. Edit: they were both raccoons, this probably isn't it
If it's neither of those, then I don't know.
Edit: Hang on, if they were manhunting animals, they probably had scaria, and there's a 50/50 chance or so that creatures with scaria will have their body instantly considered rotten upon death. Check the second body and see if it says it's rotten. Colonists won't butcher spoiled corpses.