When there is a promotion with highlight enabled and the product, which is included in this promotion, is inside a list, such as a shelf, the badge that informs the promotion is not displayed.

Product Highlight component: https://developers.vtex.com/vtex-developer-docs/docs/vtex-product-highlights

Create a featured-enabled promotion and insert a product, included in the promotion, into a list context within a page.

Create a collection with the promotion name and enable the flag Add collection tag; Add the Product Highlight in the list context with type: collection;

Creating Collections: https://help.vtex.com/tutorial/creating-collections-beta--yJBHqNMViOAnnnq4fyOye