Why can't I use the Lamborghini #63 Squadra Corse Huracán?

I completed the Forzathon event, jumping the airfield danger sign, to unlock the Horizon Edition Lamborghini Huracán, which I can use just fine.

However I've also noticed a racing version in my garage. Which is marked with a DLC marker.

When I try and select this car, the game starts looking for purchase options, and then I get this message.

Is this a bug with the game? A bug with my game save? A glitch or what? I've raced against other Drivatars using this car, so I know it's playable.

I'm playing on Windows, with the Expansion Pass and Car Pass.

This car was given away to everyone as a promotional car to celebrate the Forza Liveried Huracan in real life that ran at a real life race.

However, the actual car still needs to be purchased from the Car Pack that includes it, which is the Motorsports All Stars Car Pack. Once you've purchased the pack/car, you should be able to drive the #63 currently in your garage.

For some reason, the gift Huracan is not correctly linked to the store.

Here it is in the store https://www.microsoft.com/en-gb/p/forza-horizon-3-motorsport-all-stars-pack/9nblggh4rlgl?activetab=pivot:overviewtab