I've noticed a bug where the combination of the Nissan R89C and (contemporary) Monza track results in a crash to desktop. I've tried loading this combo twice in a row with the same result, then drove the car around Spielberg without issues. After half an hour I started the game up again and encountered the same CTD with the R89C + Monza combo.
If this part has been reported then sorry for the double post but I too have the CTD with the R89C, however, in my tests to see what the issue it is appears to only CTD when the low downforce configuration is used regardless of track selected. If I picked a track with standard downforce configuration the car loaded no issue.
They released a new update today to fix it and guess what now it loads but the audio and force feedback is messed up. Everything else works just the r89 low downforce varient