Hello @Tommy Larsen,
Thank you for providing the details. This booster cannot be displayed multiple times with different items, as it shows the products configured in the product backend settings. So, adding few of such shortcodes per one page will display the same items attached. It is designed to be used on single product pages rather than on other non-product pages.
You can find more information in the documentation: https://www.8theme.com/documentation/salesmax/main/boosters/frequently-bought-together/.
Best regards,
Jack Richardson
The 8Theme Team