That happens all the time!
I ran a few races on christmas eve where it felt more like a D-Day landing rather than a track race. I had laggy cars flying all over the track when they tried to overtake each other. First one would zip by like it did to you at 4000mph in reverse. then I would drive through a corner where there was lagged up pile of cars in mid- air around me while i pray and hold the driving line. Then the car that went by in reverse would change its mind and plow through me on the way back to the front. I went from 3rd-4th to last place each time. Annoying as hell and bad for the DR
I should add that i checked my internet connection and it was running full Mbps. So it was not my connection it was their server or other racers connections.