Check whether the whole swatch widget appears twice or extra rows appear inside it.
The whole widget appears twice
Open the product template in Shopify’s theme editor.
Check whether the Swatches app block was added twice.
If there are duplicate blocks, remove the extra block, keeping the one in the position you want.
Save the template.
If there is only one block, share the product page URL and a screenshot with support so we can check the setup.
Extra rows appear in one widget
A product added to several groups can show swatches from each group on its product page. To remove unwanted rows, remove the product from groups it should no longer belong to.
If each product should belong to only one group, use Maximum groups per product to prevent new overlapping assignments and find existing ones that need cleanup.
Follow Choosing a group limit to set the limit, review affected groups, and remove unwanted assignments.