Yeah, the updates are definitely a bit of a dog's breakfast at the moment which seems to be two sets of issues: with the underlying Steam update mechanism being unreliable, and then rF2 having "old" versions referenced.
In my case, I did a Steam verification: when it got to validating, suddenly it found another 568Mb update to download. It did that, I restarted rF2, and it duly installed the 1.43/1.42 files, Problem was, it then left the 1.25/1.24 files. Which meant my "selected" car was still the 1.25 version, not the 1.43. I manually changed that, but the opponents list basically had 2 sets of entries for the two version (i.e. two #10 cars). I then quait rF2, manually went and deleted the Competition System profile from the last IndyCar season, restarted rF2, whence it decided to remove the 1.25/1.24 versions. Though, it still gave an error in that process. Maybe I didn't have to do the manual delete of the CS file, but, that whole process is also borked.
I've got similar issues with multiple versions of Spa, for instance.