Which inventory issue must be disclosed in the notes to financial statements?

Price changes for customers do not need to be disclosed in the notes to financial statements because they are typically considered normal operational adjustments rather than transactions that could significantly impact the financial statements' integrity. These changes are part of regular business activity and are reflected in revenue recognition rather than requiring separate disclosure.

The average costs of inventory are generally part of the inventory accounting policy and are included in the financial statements themselves rather than requiring separate note disclosure. While important for understanding inventory valuation, they do not represent a significant issue that impacts the overall financial statement transparency in the same way related party transactions do.

Suppliers' net assets are not typically disclosed in the notes to financial statements as they pertain to the financial position of external entities rather than the reporting entity itself. The focus of the notes is on the entity's financial performance and position, making this information irrelevant for disclosure purposes.