New item not found on relation widget (in the same browser used to create it)

[PedroOndh]

Describe the bug
When i add a new entry in author collection appears on the list, but it is not selectable through the relation widget from other articles.

If I hardcode the id of the author, Netlify CMS doesn't find it and return an error. If I access from any other browser or in incognito mode this error disappear and the author is found. But the error remains even after cleaning the cache on the original browser.

To Reproduce

1. Go to collection A and create a new item
2. Go to an item on collection B and search in the relation widget (connected to collection A) the new item
3. Item is not found, if hardcoded Netlify CMS will return an error.

Expected behavior
Find the new item in the collection

Screenshots

Applicable Versions:

• Netlify CMS version: 2.10.81
• Git provider: BitBucket
• OS: macOS Catalina
• Browser version: Chrome (maybe happens in other browsers, but as it's dependand on cookies/localStorage or some similar issue couldn't replicate it)

CMS configuration

backend:
  name: bitbucket
  repo: xxxxxx/cbn-jekyll-cms # Path to your Bitbucket repository
  branch: develop
  auth_type: implicit
  app_id: xxxxxxxx

# for using local backend run "npx netlify-cms-proxy-server" and enter in /admin
local_backend: true

media_folder: "assets/media/uploads"
logo_url: https://xxx/assets/media/logo/logo-animated.gif
display_url: https://xxx

collections:
  - name: "blog"
    label: "Blog"
    label_singular: "Blog post"
    description: "Entries sortable by Publish Date or title on 'Sort by' button"
    folder: "collections/_posts"
    filter:
      field: "categories"
      value: "blog"
    sortable_fields: ['publish-date', 'title']
    view_filters:
      - label: '2020'
        field: "publish-date"
        pattern: '2020'
    create: true
    slug: "{{year}}-{{month}}-{{day}}-{{slug}}"
    fields:
      - {label: "Layout", name: "layout", widget: "hidden", default: "post"}
      - {label: "Post Category", name: "categories", widget: "hidden", default: "blog"}
      - {label: "Post Author", name: "author", widget: "relation", collection: "team-members", search_fields: ["name","email"], value_field: "email", display_fields: ["name"], required: false}
      - {label: 'Cover Image', name: 'image', widget: 'image', tagname: '', hint: "File type: PNG / File size: as small as possible (Ask designer)"}
      - {label: "Publish date", name: "publish-date", widget: "datetime", format: "YYYY-MM-DD HH:mm a", default: ""}
      - {label: "Title", name: "title", widget: "string", tagname: "h1"}
      - {label: "Subtitle", name: "subtitle", widget: "string", tagname: "h3", required: false}
      - {label: "Permalink", name: "slug", widget: "string", hint: "The URL of this post. WARNING: IF YOU EDIT THIS FIELD YOU CANNOT LEAVE IT BLANK", pattern: ["^[a-zA-Z\\-0-9]+$", "Must not have whitespaces and not being empty"], required: false}
      - {label: 'Meta Description', name: 'description', widget: 'string', required: false}
      - {label: "Body", name: "body", widget: "markdown"}
      - {label: "Tags", name: "tags",  widget: select, options: ['Products', 'Engineering', 'Customers', 'News', 'Retail', 'Insights', 'Search', 'UX'], multiple: true}
[...]

  - name: "team-members"
    label: "Team Members"
    label_singular: "Team Member"
    folder: "collections/_team-members"
    create: true
    slug: "{{slug}}"
    sortable_fields: ['name']
    identifier_field: name
    fields:
      - {label: "Name and Last Name", name: "name", widget: "string"}
      - {label: "Job title", name: "jobtitle", widget: "string"}
      - {label: "Image", name: "image", widget: "image"}
      - {label: "Team", name: "team", widget: select, options: ["Leadership", "Search", "Interface", "Data", "UX","Operations","DevOps","Enterprise","Delivery", "Play", "Motive"]}
      - {label: "Email", name: "email", widget: "string"}
      - {label: "Description", name: "body", widget: "markdown", required: false}
      - label: "Social Media"
        name: "social-media"
        widget: "list"
        required: false
        fields:
          - {label: Social Media Name, name: name, widget: select, options: ["Facebook", "Twitter", "Instagram", "Linkedin", "Google"]}
          - {label: URL, name: url, widget: string, hint: "For example: https://www.instagram.com/username/"}
      - {label: "Birth date", name: "birthday", widget: "datetime", format: "YYYY-MM-DD HH:mm a", default: "", required: false}
      - {label: "Tags", name: "tags",  widget: select, options: ['Products', 'Engineering', 'Customers', 'News', 'Retail', 'Insights', 'Search', 'UX'], multiple: true}
      - {label: "Active", name: "active", widget: "boolean", default: true}