Deep Copy Failed- Destination Empty

I am trying to open a seperate window where it will display the basics of the room you’re in- the obvious exits, visible NPCs, and obvious takeable items.

This works in many rooms. Some rooms give the error message “deep copy failed— destination empty”. I don’t know if this is because there are too many possible objects, or if the parser is confused as to whether an item qualifies. When you leave the room, it works again, and when you re-enter the room, again it does not.

Any thoughts? I wish i could be more specific.