The tracker udp://tracker.torrent.eu.org:451/announce gives `error response: "Connection ID missmatch.\x00"` every 2 minutes when under heavy use. I suspect that reconnect requests are sent just after the connection ID is confirmed as not stale, but before it used for a request, and the server rejects the request after processing the reconnect first.
It might also just be that that tracker server implementation is lazy and marks everything stale on regular boundaries.
Matt Joiner