So I have been racing the endurance pack since launch and I have had an issue now and again where the vehicles disappear in game, but if I close and restart they re-verify and reappear. However, today they have gone and they won't come back. I have verified the game file several times and don't see a way of unsubscribing and resubscribing to s397 DLC content. Any suggestions?
You will find the content in your steam inventory, where you can unsubscribe and resubscribe. This often fixes issues.