Solved

What's that "halo" effect thingy around some cars during live race?

I notice it comes and goes on certain cars. I thought it might be indication of push but it doesn't relate to what my car is doing.

I think you may be talking about the rotating circle that appears around the car you have selected in the race viewer. But if the halo is appearing on cars the camera is NOT following, that's another problem entirely...

There is a halo for first, second and third places which provide visual references.

Ah, that's it.... 1st, 2nd & 3rd. Thanks.