Strange, I was seeing two products listed in that menu when I checked into it yesterday, though only one of them was actually selected for the bundle product you'd created. Are you saying you saw only one product listed in the menu that appears when you checkmark "Package files from other products"?
You've added some more products since then, so now I'm not sure which product is meant to be the bundle vs. which ones are contributing files to that bundle, but bear in mind a product can either issue a file download of its own OR issue files uploaded to other products, but NOT both -- i.e., a product cannot issue a file uploaded to itself and also issue files uploaded to other products.