fireworks that bounce off of slime blocks dont explode

What I expected to happen was the firework to explode after bouncing

What actually happened was it acted as if it wasnt colored

Steps to Reproduce:
1. make a firework with a colored explosion
2. fire it from a dispenser then an observer with a 2.5 redstone tick delay connected to a piston pointing at the dispenser with two blocks of slime on top of each other, 7 blocks in between the slime blocks and the dispenser
3. the fireworks will not make an explosion