I joined a session in progress (matchmade) of Flood, but this happened: I spawned with a DMR, a Magnum, and nothing else. I was NOT listed on the leaderboard. Both survivors and Flood showed up as enemies to me. Flood players were not able to infect me yet I was able to infect survivors. It only lasted for the first round. You can watch the clip in my file share.
Has anybody else experienced this?