Taxonomies & custom texonomies don’t work

After the update to version 4.0.x, taxonomies and custom taxonomies to custom post types do not work. On the site, when one of these are clicked it comes up with the following error:

Fatal error: Uncaught Error: Call to a member function has() on null in /home/…/public_html/wp-content/plugins/all-in-one-seo-pack/app/Common/Meta/Title.php

In the aioseo admin, there is nothing under Search appearance > Taxonomies. It’s just blank!

The site has various custom taxonomies under a custom post type for films. All worked fine under the previous versions up to and including 3.7.1.

I have had to rollback to this version to get the site working.