When using a preset Superflat world and assigning a wrong biome name the game crashes

What I expected to happen was...:
I expected the preset to reset to a default form when you messes up the biome name

minecraft:bedrock,2*minecraft:dirt,minecraft:grass_block;minecraft:plains

as when the block layers script is wrong

What actually happened was...:
The game crashes

Steps to Reproduce:
1. Create a new world
2. Superflat >> Costumize >> Presets
3. Change the biome to anything wrong;

minecraft:bedrock,2*minecraft:dirt,minecraft:grass_block;minecraft:anything_wrong

4. Press "Use preset"
5. Press "Done"
6. The game crashes

(Crash report attached)