Use hasOwnProperty for linkquality check. https://stackoverflow.com/questions/13632999/if-key-in-object-or-ifobject-hasownpropertykey

lib/controller.js

@@ -319,7 +319,7 @@ class Controller {
                 });
 
                 // Add device linkquality.
-                if ('linkquality' in message) {
+                if (message.hasOwnProperty('linkquality')) {
                     payload.linkquality = message.linkquality;
                 }