Option "unique" doesn't work

Hey there, I'm trying to build a simple collection to get emails from the main website (using the REST API)

Here's my collection:

import { CollectionConfig } from 'payload/types'
import { loggedIn } from './access/loggedIn'

export const Newsletter: CollectionConfig = {
  slug: 'newsletter',
  labels: {
    singular: 'Newsletter',
    plural: 'Newsletters',
  },
  admin: {
    useAsTitle: 'name',
    defaultColumns: ['name', 'email', 'updatedAt'],
  },
  access: {
    read: loggedIn,
    create: () => true,
    update: loggedIn,
    delete: loggedIn,
  },
  fields: [
    {
      name: 'name',
      label: 'Nome',
      type: 'text',
      index: true,
    },
    {
      name: 'email',
      label: 'Email',
      type: 'email',
      index: true,
      unique: true,
    },
  ],
}

Although email has a

, it allows me to make multiple requests with the same email and all get saved in the database (as the image attached shows)

Any ideas?