I have noticed a bug in the heroic race wheel boost. I used the free spin yesterday afternoon, which means that the next free spin would be this afternoon. However, I have payed for 2 spins (40 gems in total) earlier today, and the timer for the free spin got reset. This means I cannot spin for free today, but only tomorrow at noon.
I honestly doubt this works as intended, and I would like my free spin bag, as it is not fair to lose a free spin due to paying for one!