Update InAppBrowser.java

src/android/InAppBrowser.java

@@ -790,7 +790,7 @@ public class InAppBrowser extends CordovaPlugin {
                     settings.setUserAgentString(overrideUserAgent);
                 }
                 if (appendUserAgent != null) {
-                    settings.setUserAgentString(settings.getUserAgentString() + appendUserAgent);
+                    settings.setUserAgentString(appendUserAgent);
                 }
 
                 //Toggle whether this is enabled or not!