Check attribute configuration:

Ensure that the attribute is configured correctly with its variants in the product configuration settings. Make sure there are no duplicates or unnecessary variants.

Verify product variables:

Double-check the variants assigned to each product. Ensure that each product only has the necessary variants assigned and that there are no duplicates.

Update attribute values:

If you find duplicate attribute values, remove the duplicates and update the attribute values to ensure each value is unique.

POS configuration:

Check the POS configuration settings to see if there's any option related to how variants are displayed. There might be a setting that needs adjustment to prevent the duplication of variants.

Update to the Latest Version:

Ensure that your Odoo instance is updated to the latest version. Sometimes, issues like this are resolved in newer versions through bug fixes and improvements.

Clear cache:

Clear the cache in your Odoo instance to ensure that any changes made to the attribute and variant configurations are reflected properly.

Database Integrity Check:

Perform a database integrity check to ensure there are no inconsistencies or conflicts causing the duplication of attribute values.

Contact Support:

If the issue persists, contact Odoo support for further assistance. They may provide specific guidance or a fix for the problem.

By following these steps, you should be able to resolve the issue of attribute values being repeated in Odoo v17 when assigning variants to products in the POS.