How can I make a kit that has Unbreakable Items in it?

I’m trying to make kits with Unbreakable Items in it for my Kit PvP server.

To make the items Unbreakable, I use this command:

 /give (Name) minecraft:(item) 1 0 {Unbreakable:1}

For proof that the command worked, I hovered over the item and it clearly said Unbreakable at the bottom of the lore. For example:

Problem is, when I do /createkit, it transfers the item but not the Unbreakable effect.

When I hover over the item after I create the kit, it does not say Unbreakable at the bottom of the lore. Again, for example:

kits:
  tools:
    delay: 10
    items:
      - stonesword 1 Unbreakable:true