I experienced an issue, where i could not see the opponent car in multiplayer race. However, the opponent was driving and could see me(my car). Also the chat and messeges indicated that the opponent was actually driving while from my perspective the Map showed the opponent position on start (but car invisible)

This happened to me in two races on the same server.

The first time, I was in the same apartment on the same server with someone, so I could see that my car was visible.

The second time it happened to some foreign opponent. I saved the replay from this race - see attached file.

If you bring up your connection list with the N key, there's a button that says UDP, clicking it will toggle between UDP and TCP.

If you can't see anyone else on track, changing to TCP will often fix the problem.

Gut zu wissen, danke! Ich werde es versuchen, wenn dieses Problem erneut auftritt.