Had a couple of situations:
- Deconstructed a bed in a prison. Metal was not able to be retrieved. Changing beds to make the room not a prison immediately fixed it.
- Colonist was incapacitated in the prison. Weapon was not retrievable. Again, making it not a prison fixed the issue.
For obvious reasons, changing the prison bed priorities is not always an option if you have prisoners. I would consider this a bug.