For some stupid reason(s), for the current Forza Horizon(FH5), barns finds cars ended up being changed to where you can’t be able to sell any of them on the auction house after acquiring each of them. Anyway, so given this, for the next Forza Horizon(FH6), it should get changed back to being where once you acquire each of the barn finds, you sell them on the auction house if you want & then for all future Forza Horizon that come out after the next Forza Horizon(FH6) has come out, this should then stay being this way regarding barn finds.