This had happened to me quite a few times, the credit or influence reward menu would say I finished 3rd when I finished 1st! The list that appears at the end of the race shows I’m first, and I got all 60 points for the championship. I am playing solo for the championship so it shouldn’t be a lag issue.
Example: https://i.imgur.com/V117F8U.jpg
Your difficulty isn’t high enough.
The requirements are usually as follows:
Place 3rd against x Drivatars
Place 2nd against y Drivatars
place 1rst against z drivatars.
x<y<z
Highly skilled is usually the highest it’ll go outside of the trial.
I play with Unbeatable all the time
Then I would suggest that you contact support.
But fact that it took you 7 months to write again, might suggest its not much of a problem to you?
