Remove some memory

Signed-off-by: yoyosource <yoyosource@nidido.de>

BauSystem_Main/src/de/steamwar/bausystem/features/shieldprinting/ShieldPrinting.java

@@ -111,6 +111,15 @@ public class ShieldPrinting implements Listener {
         }
         shieldMap.keySet().removeAll(toRemove);
         shieldMap.putAll(temp);
+
+        toRemove.clear();
+        for (Map.Entry<Vector, Vector> entry : shieldMap.entrySet()) {
+            if (entry.getKey().equals(entry.getValue())) {
+                toRemove.add(entry.getKey());
+            }
+        }
+        shieldMap.keySet().removeAll(toRemove);
+
         updateBossbars();
     }