Autofixer Discount Shard broken?

[TypeDefinition]

It shows 12 in my inventory, but I only have a 24% discount. And when I buy a vehicle the number doesn't go down.

[Graf Erik]

The things in your inventory are used shards. A discount shard works only once, it gives you one discount.
For the first shard you get 24%. Two gets 39%. With every additional shard it rises, up to 100% discount at 13 shards, yes, that a free car. One free car.
If you buy a car, the discount is used up. The used shard stays in your inventory.