Enchantment seed is reset every time the world is closed and opened.

Expectation: When closing and reloading a world, the enchantments available for an item at an enchantment table should be the same before and after the world is loaded.

Reality: When a world is closed and reopeoned, the enchantments for every item are reset to the same static list of available enchantments per item.

The enchanting seed is reset every time the world is loaded, as opposed to being saved with the world.

Every single time a world is closed and opened, the enchantment table is set to offer the same enchantments for every item. After enchanting an item, the enchantment seed seems to change randomly as it should. The enchantment seed should persist through world saves and reloads.

E.G.
After loading a world, the available enchantments for a book at a level 30 table are always
Power 1
Fire Aspect 1
Fortune II.

After enchanting an item once, however, the subsequent available options are unpredictable, as they should.