When you craft a high amount of Firework Rockets, but don't have a high amount of Firework Stars, if you use Shift + Click to create the Firework Rockets, you will make the Firework Rockets with the crafted Firework Stars, but also Firework Rockets with no Firework Stars. Resulting in having the customized Firework Rockets and empty Firework Rockets.

Same issue happens with Firework Stars, and possibility other items that use shared crafting recipes.