This error can sometimes occur if a blank product group has been created.
Please check Product Groups within Inventory to ensure no blank named product groups have been created.
If a blank named product group has been created, please reassign any SKUS in that group and then contact support to delete the group.
Please try refreshing the settlement via the Action menu on your settlement.
If the refresh does not clear the error please open a conversation with support via the blue chat icon on the bottom right of any page.