When you create a product with multiple pricing tiers, putting that product in a bundle automatically unlocks all pricing tiers (for those who buy it), even though the asset only shows the base price when calculating percentages on the sale/bundle creation tool.
This means that I need to create separate assets for each pricing tier if I want to include only the base product in a bundle. This might be a design decision on itch's part, or just an oversight, but it limits my ability to control pricing and sales of my products.