Daytona Oval

I was racing online the other night in a private lobby with 6 racers and then filled the lobby with drivertars. Mainly on the embankment part of the oval the drivertars seemed to sink below the track and then pop back up on the flat straights. I have a replay saved which I need to check if it shows the same thing on that too. It was very strange and made it very hard to overtake the cars and also caused the car to almost crash if one went under you or you hit one. The cars vanished to just below the roof so you could just see the tops of the windows.