Bug on the number of servings and sales in display cases

I got the sweetest treat display case from the newest expansion and I'm pretty sure this is a bug. When I cook a dish that has many servings and displayed it there for sale, the amount of sales I got from it when a customer buys is the same as when I sell 1 serving of it.

For example, a dish that is worth $20 and has 8 servings should give me $160 when the customer buys the entire dish but I only got $20. 

Is anyone else experiencing this?