Ideas
"Good" to see that i´m not only one who encountered this.
It was also my second season and i signed Bortoleto as my number 1 driver. I actually changed the good parts for him and did a very good practice session in Australia. Then i saved the game because i had to go to do something.
Then i did play again and on to the Q1. I had no pace at all, i couldnt even win my teammate who should have had a lot worse car than i. Same in race, had no pace at all and was super confused. Then i went back to assign upgrades menu and noticed that all the parts were on my second driver again and now i can´t move them anymore and the new upgrades goes to wrong driver also. So in the middle of race weekend while saving and loading the game, those parts jumped back to my other driver somehow :D
Really hope they fix this.