If you look at this site
it shows the time trial leaderboards including further details such as whether assists have been used. I am a PC user.
I wanted to compare my times with comparable drivers, for example, it is a bit pointless if you are using a wheel, pro handling, and no assists in a lotus 49 comparing yourself to someone using a gamepad, novice setting and all assists on including steering assist and braking assist. It is a completely different thing.
I found that when I looked at these tables it said I was using abs, traction and stability control (even though I wasn't). And before you ask there were definitely off. I used the external view where you can see whether they are on or off in the display. I also tested the driving and you could tell they were off, the brakes locked up easily in comparison to when I tried with assists forced on. I did the test in a Lotus 49 which does not have modern assists (however this bug seems to have happened in all my time trial results).
After a bit of experimentation I found that if you use "real" assists in the settings it says you have abs, traction and stability control turned on even when you don't.
I was hoping that at a later stage the leaderboards in game would feature information about assists used (and I know others have asked for this). Now it seems a bit pointless since all the data is corrupted.
The reason I think this is a in game bug and not a problem with the website is I also I could not get the "I am the 5% trophy" even though all assists were off, I was using internal cam etc (I was using all the correct settings, didn't work if I had real settings on or forced all assists off). I have a feeling the reason for this may be related. I ended up deleting my save game and starting again. This is the only way I could get the trophy to work. After I did this it worked easily. So I think this bug is throughout the game about how it records what assists are being used.