Expected behaviour:

If you have an item with a max stack size greater than 1, dropping it and picking it back up should make it automatically stack.

What happens instead:

Under certain conditions, the items don't automatically stack and you have to manually stack them again.

How to reproduce:

• /give @s minecraft:diamond_sword[minecraft:max_stack_size=2] 2
• While holding both items, damage them once
• Drop one item from the stack
• Notice how it doesn't go back to the original stack