Game difficulty setting doesn't save within a world

I'm having 2 different problems.

1. The game difficulty setting is not kept when you exit your world.

2. While in world, I cannot select the game difficulty "Hard" until I have selected the difficulties Normal or Easy first.

Steps to Reproduce

• Create a new world.

• Set the game difficulty to Peaceful.

• Create the world.

• While you're in the world change your game difficulty to Hard.

• You may not be able to select the game difficulty until you select Easy or Normal first.

• Once the game difficulty is set open the menu again.

• Notice that the game difficulty is correctly set to "Hard".

• Close your world.

• Edit your world.

• Notice the game difficulty is set to Peaceful again!