Ok, I nominate this for bug of the year. I'm surprised that can happen. I guess it's treating it as two different clients connecting from the same IP. The server distinguishes between clients like that by using random number. I would expect one of two clients with the same number to be dropped, but I guess somehow you sent two connection requests, got the same number assigned to both, and the server spawned two clients with the same number, and looped through and applied the same inputs to both. That must have looked hilarious from an observer's perspective with your synchronized jumping.