What is the difference is between the foreign owned assets category in the financial account and the capital transfer category of the capital account?

Capital transfers include debt forgiveness and migrants transfers (goods and financial assets belonging to migrants as they leave or enter the country). Capital transfers also include the transfer of title to fixed assets and the transfer of funds linked to the sale or acquisition of fixed assets, gift and inheritance taxes, death duties, uninsured damage to fixed assets, and legacies.

Foreign-owned assets in the reporting country include securities issued by the reporting country's government and private sectors (e.g., bonds, equities, mortgage-backed securities), direct investment, and foreign liabilities reported by the reporting country's banking sector. e.g. UK government bonds owned by Chinese investors.