Extra Permissions entered twice into AndroidManifest.xml

When entering an extra permission for the AndroidManifest.xml from within the project settings it get's inserted into the AndroidManifest.xml two times instead of one.

when I enter:

com.android.vending.BILLING

The actual manifest upon building shows

 <!-- Requirements -->
 <uses-sdk android:minSdkVersion="9"/>
 <uses-feature android:glEsVersion="0x00020000" android:required="true" />
 <uses-permission android:name="android.permission.INTERNET"/>
 <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
 <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
 <uses-permission android:name="android.permission.WAKE_LOCK"/>
 <uses-permission android:name="android.permission.READ_PHONE_STATE"/>
 <uses-permission android:name="com.android.vending.CHECK_LICENSE"/>
 <uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
 <uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS"/>
 <uses-permission android:name="android.permission.GET_ACCOUNTS"/>
 <uses-permission android:name="android.permission.VIBRATE"/>
 <uses-permission android:name="com.android.vending.BILLING"/>
 <uses-permission android:name="com.android.vending.BILLING"/>