Put the summary of the bug you're having here

What I expected to happen was...:
Spectator Hotbar appears after pressing any keys from 1-0

What actually happened was...:
Instead when pressing keys 1-0 game crashed

Steps to Reproduce:
1. Enter singeplayer (didn't test multi) with bundle and 1.20 enabled
2. Enter spectator mode
3. Press any keys 1-0

Exact Error code:

 
The game crashed whilst unexpected error
Error: java.lang.NullPointerException: Cannot invoke "exp.a()" because "$$0" is null