When you shoot a Firework with a Crossbow, it will keep the texture of the loaded Firework on the Item Bar after shooting it if you don't have more Fireworks in reserve.
To reproduce:
Load a Firework on a Crossbow
Drop or Store any Arrows or Fireworks left (if any)
Shoot the Firework
See how the Crossbow still shows a Firework loaded on the Item Bar
I tested on a Survival Dedicated Server and a Local Creative World.
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However, this issue is a Duplicate of MCPE-53545.
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