Found several bugs after some extended play. This is on XBox One X v.4.0.0.1.0992. I sure hope these have already been acknowledged and will be fixed soon:
1. When under an AI-controlled rolling start, the player's car will sometimes run into the car ahead, causing damage and sometimes incurring a penalty. For example, this happens quite frequently at Daytona RC with 20 AI and multi-class (LMP2, GTE, GT3) when I start at the back of the LMP2's. At the very least, why not make the player's car invulnerable while under AI-control, if it is too hard to properly fix the issue with AI/spacing?
2. Pop-up invisible wall shadows on track at night. I'm not sure how to properly explain this one, but I have noticed at night there will be these small invisible squares on the track that sort of "appear" out of nowhere as you approach them and cast a shadow right in front of the car. At first I thought it was some sort of phantom smoke, but then I realized it's some sort of shadow. It was very unsettling at first - now it's just immersion-breaking. I have seen this at Daytona, Le Mans, and Laguna Seca, and I suspect all tracks have this issue. I have seen this in Youtube videos as well so I know it's not just me.
3. AI cars disqualify themselves when entering the pits - presumably from entering too fast. This seems to happen more on certain tracks than others, and possibly more with certain classes. It will still occur even if all rules are turned off. For example, GTE seems to have a huge problem with this at Daytona RC. I ran an 18 lap "24 hour" race at Daytona RC with 20 AI (LMP2, GTE, and GT3) and a required pit stop. By the end of the race, 5 out of 7 GTE cars had disqualified themselves from the 1 pit stop, and 2 out of 7 GT3 cars had done the same. This is game-breaking for offline endurance racers.
4. Replay save failure. I wanted to save the replay of my above 18-lap race with 20 AI at Daytona RC so I could take screenshots at my leisure. Unfortunately, after a rather lengthy wait for the "save" to process, I got the error "Failed to save media. Do you want to retry the save?" Retrying the save produced the same result. I only have 1 replay saved on my system, and I only have 2 games on my otherwise brand new XBox One X (Pcars 2 and Forza 7) so space is not the issue. I did have time cranked up to 60x to simulate the day/night transition - I wonder if there is some time/compression bug messing with the save.
5. Corner pathing at Indy oval. I have noticed, especially with vintage Indy Cars, that going into turns 1 and 3 the AI will cut down so far that they will frequently end up with all 4 wheels on the grass to the inside of the turn. This often leads to 1 of 2 results: either the car will pull down onto the access road to the inside of the turn and give up a ton of time, or it will hit the brakes and pull back up into the "groove" on the track - all too often creating horrendous wrecks in the process. This is immersion-breaking in either event and could definitely use some tweaking.