Witness: Fixing a world bleed issue with multiple Witness seeds, prev…

…enting generation (ArchipelagoMW#2031)

Co-authored-by: blastron <[email protected]>

worlds/witness/items.py

@@ -99,7 +99,7 @@ def __init__(self, multiworld: MultiWorld, player: int, logic: WitnessPlayerLogi
         self._locations: WitnessPlayerLocations = locat
 
         # Duplicate the static item data, then make any player-specific adjustments to classification.
-        self.item_data: Dict[str, ItemData] = copy.copy(StaticWitnessItems.item_data)
+        self.item_data: Dict[str, ItemData] = copy.deepcopy(StaticWitnessItems.item_data)
 
         # Remove all progression items that aren't actually in the game.
         self.item_data = {name: data for (name, data) in self.item_data.items()