I'm familiar with DynDNS and the client. The client tries to detect your external IP address in order to keep your dynamic DNS record pointed at your current IP. It looks to me like you're running it on a machine that's routing through Tor. So it picks up the IP address of the Exit you're routed through, and incorrectly tries to update your dynamic DNS with this Exit IP instead of your actual IP.

If this theory is correct, there's not really a "bug" here. It's working as expected. You can't run the DynDNS client if you're routing traffic through Tor.