When a crossbow is loaded with a firework/arrow and shot, it will keep the loaded sprite in the hotbar with the corresponding ammo. If you go into the inventory and look at the hotbar, it will just show a loaded arrow even if it was a firework. The only way to resolve this is to put in in the inventory, close it, and put it back over, but the problem will start again and continue.
Thank you for your report!
We're actually already tracking this issue at MCPE-53545, so I will resolve and link this ticket as a duplicate.
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