When interacting with a villager with the villager trade rebalance enabled, if that villager's career and level could generate ItemAndEmeraldsToItems type trades that sell enchanted items (e.g. plains armorer), then the game will crash.

To reproduce:

1. Create a new world. Make sure the villager trade rebalance is enabled.
2. Level an armorer up to either expert (does not apply to expert level taiga villagers) or master level.
3. Save and quit the world.
4. Reopen the world.
5. Interact with the armorer.
6. The game will crash.

I've also attached both a crash report from a vanilla client and one that is deobfuscated with the official mappings.