How can I hide the attributes because it's not working?

[soft stump]

    material: spawner
    slot: 11
    display_name: '&eVault #1 &a[ᴜɴʟᴏᴄᴋᴇᴅ]'
    hide_attributes: true
    lore:
    - '&8ᴘʟᴀʏᴇʀ ᴠᴀᴜʟᴛѕ'
    - ' '
    - '&#9cafbfStore &cvaluable &#9cafbfitems in'
    - '&#9cafbfthis &csecure &#9cafbfstorage space.'
    click_commands:
        - '[player] playervaults:pv 1'```

[torn cobalt]

Update to the latest dev build from jenkins: https://ci.extendedclip.com/job/DeluxeMenus/181/

[soft stump]

I did this, still nothing

[torn cobalt]

what server version?

[soft stump]

1.21.4, paper

[slow vector]

item_flags:
  - HIDE_ADDITIONAL_TOOLTIP

https://hub.spigotmc.org/javadocs/bukkit/org/bukkit/inventory/ItemFlag.html