I don’t think 25% off sales work that way on itch. You have the game marked as pay-what-you-want, and you have a minimum price on the non-free asset. Because it has a minimum price, it’s not affected by sales. If I pay the sales price, then I haven’t paid the minimum price and won’t get the non-free asset.
A better way to handle this would be to set a price for the entire project, and mark the free version of the asset as “free demo”. That way sales events will work properly.
Source: itch.io