Some people already reported some content missing after the new update. In my case it's the ISI road cars (NSX and Corvette) as far as I could tell. Unsubscribing and re-subscribing does nothing. Here are some posts from other people as well.
I am finding this also. Much of my content is missing in game (I'd say around half of my subscribed items are not present). The 'Installed\Locations' folder is also missing this content (eg. Bathurst). When I visit the Workshop I can see I am still subscribed to Bathurst. Unsubscribing and re-subscribing doesn't help - and the details in the workshop say that Bathurst is 0.000MB.
I'm having this issue with basically all of the stock game content. Unshbscribed and resubscribed. Restarted PC. Restarted steam. Uninstalled and reinstalled. Nothing worked.
Thank you Marcel and team. I now see in the Workshop that Bathurst is 343MB again (instead of 0MB). I did have to unsubscribe and resubscribe to get it to download. And then it all works as expected from there. Thanks again. I'm guessing I'll need to go through the Workshop and resubscribe to anything I'm missing again.