Note: This also works for removing those pesky skeletons from your settlements.
This is technically not a bug and more of a development oversight and may be patched in the future however this fix will solve this issue. From time to time you will come across a new settlement, shoot all of the baddies and take over, some of these settlements have corpses placed by the developers to make it look like a hostile environment. This was probably done as a way to encourage the player to clean up and get creative however these corpses never go away.
To remove these corpses follow the following steps. For this example I am using the dead dog and human outside of sanctuary.
Step 1. Find the corpses you want to get rid of.
Step 2. Look at the corpse(s) you want to remove.
Step 3. Open up the command console, click on the corpse(s) you want to remove and enter the ‘markfordelete’ command.
Step 4. The corpses will now be removed from the game on the next refresh of this area, to trigger this refresh you can wait for two in game days at a location that is far from the corpses or you can save the game, close the game to the desktop and then launch the game again. Quick saving and Quick loading may also work but I found it has mixed results.