If I run the Pricelist / Pricelist with Quantity Breaks I can see a product that I do not have a Quantity Break set up for.
No Quantity breaks on the product.
Why is this showing?
The product on the pricelist is not showing a Price Level. To make the missing price level active again, go into Admin / Defaults / Manage Product Defaults - Price Levels and label the price levels.
Open the Pricing tab on the product, one of the blank price levels has a quantity break set.
Remove the pricing and save the product.
Go back and delete the names on the Price Levels in Admin / Defaults / Manage Product Defaults