Metatag: Current Page Title Override

Provides an additional field in the Basic Metatags section to allow you to override the [current-page:title] token.

This allows you to retain your sitewide patterns (such as [current-page:title] | [site:name]) and means your editorial team are less likely to cause SEO issues by forgetting to add the pattern tokens back when overriding the existing Page Title field.

Why not try this out on:
https://simplytest.me/project/metatag_current_page_title_override

1) Go to the link above and deploy the site.
2) Enable this module and its dependency, Metatag & Token.
3) Go to the Basic Page Content Type settings
4) Add the MetaTag field
5) go the Configuration section, then Metatags
6) Edit the Content and change the default page title token template for nodes to:
>[current-page:title] | [site:name]
(ie, it should not be using node:title anymore.
7) Create a new Basic Page node. Enter something into the Title and Body. Now expand the MetaTags fieldset and enter something in the "Current Page Title override" field (different to the node title). Hit Save And Publish.
8) If this worked, your Page Title (the one in the tab) should contain your override, not the Node Title.