Items which traditionally do not stack cannot be enchanted in an enchanting table.

Steps to Reproduce:

1. Get the following item:

   /give @p minecraft:netherite_chestplate[minecraft:max_stack_size=2] 2
   

2. Try to enchant one of the chestplates
   → The item cannot be enchanted
3. Get a 'normal' netherite chestplate
4. Try and enchant it
   → Enchanting is possible

Screenshots/Videos:

EnchantMaxStack.mp4

Notes:

1. This behavior is not specifically applicable to all components applied to an item, as trying the same thing with an item that has a food component can properly be enchanted (demonstrated in the video)
2. This behavior does not apply for items which can normally stack to 64 and can be enchanted, such as books.