I would say Data Result should say that.
Promotions are not based on Product? in that case fact 2 should have Product right?
Promotions are not based on product. The business behind is the promotions here are applied to transactions (sales), not on particular product.
Try to create a Fact in BMM with 2 LTS: Sales and Promotions and define level-based measures.
As both facts share the branch and time dimensions (conforming dims), OBIEE will join the facts with these columns.