This issue appears on almost all cars with a stock automatic transmission in this game. In the case of this Koenigsegg, the shift time is also egregiously long, making the car behave weird when shifting gears on corners. When Telemetry view is on, I can see the clutch input at 100% during a gear change for a concerningly long moment.
I’m sure this is not intended behaviour because in previous Forza games that featured this car, the shift time was pretty much instantaneous, and any Geabox or Clutch upgrades did not improve shift time as it was already fast enough. On the other hand, they always required clutch input when ‘Manual w/ Clutch’ setting was applied.
I will provide a video showing the behaviour of the One:1 in Motorsport, Motorsport 7 and Horizon 5 later.