I have read a few threads about similar problems, where other cars suddenly disappear, but all else still works. From what I have read, it seems the finger is being pointed at Linux servers. I don't know enough to say if this is correct, but I have been having problems on lots of different servers. Problem is:
1. Other competitors suddenly disappear and small map freezes.
2. Next lap around, get yellow flag warnings before driving through a swarm of Lag Timers (just like driving through a swarm of bees)
3. Race position number fluctuates wildly (one minute I'm in 1st, next I'm down to 7th or 8th)
4. Overall timing of race is unaffected. Race will finish and all details show up correctly (times, placing etc)
5. Bars are not doing anything strange at all
6. No one times out and msgs are still working OK

I have only been having these problems since the latest update was released.
As a non-tech person, I don't know how to go about isolating the problem and solving it, so any GOOD help will be appreciated.