Well, I was messing with crafts in vanilla and then this happened:
https://www.youtube.com/watch?v=zM8oo9xojic&feature=youtu.be

At first, after crafting the totem of undying (i tried both 2 and 1 totem of undying) all recipe components duplicated (but only graphically), after touching any of them they return into a normal state.

Here is the code, that I used to create the recipe:

{
    "type": "crafting_shaped",
    "pattern": [
        "#O#",
        "ENE",
        "RER"
    ],
    "key": {
        "#": {
            "item": "minecraft:emerald"
        },
        "O": {
            "item": "minecraft:observer"
        },
        "E": {
            "item": "minecraft:end_stone"
        },
        "N": {
            "item": "minecraft:nether_star"
        },
        "R": {
            "item": "minecraft:redstone_torch"
        }
    },
    "result": {
        "item": "minecraft:totem_of_undying",
        "count": 2
    }
}

The recipe is called totem_of_undying.json

I created it in Sublime Text program.

Then I placed in in the directory C:/Users/Татьяна(My Russian Username)/AppData/Roaming/.minecraft/saves/My datapack testing world/datapacks/multivanilla_plus_plus/data/uncraftable/recipes
(I was doing it all while my minecraft was open)

Then I executed a command /reload and it gave me the error in chat:

Duplicate recipe ignored with ID uncraftable:totem_of_undying

And then the things in the video happened.

I placed all of the ingredients into the crafting grid, then I took 1(or 2) totem of undying and all components duplicated. Also, you can stack totems if you put the 2-stack on another n-stack.

Futhermore, I found out that totems can be picked up in stacks of 2.

Almost all things listed before you can fing in the video on youtube that I posted.

(I was chatting with a friend on Skype. Do not pay attention to it.)