Properly handle disconnects in voice when force disconnected

discord/voice_client.py

@@ -252,6 +252,10 @@ class VoiceClient(VoiceProtocol):
 
         if not self._handshaking:
             # If we're done handshaking then we just need to update ourselves
+            if channel_id is None:
+                # We're being disconnected so cleanup
+                await self.disconnect()
+            else:
                 guild = self.guild
                 self.channel = channel_id and guild and guild.get_channel(int(channel_id))
         else: