The above error is coming into my console and means that I'm unable to edit posts across the site, I believe this is because it prevents the JS loading which brings in the WSWYWIG editor.
I believe this has been caused by using rename an imported custom post type from authors to authors-cpt.
How do I amend the relationship to make this work again?
Can I get some more specific details about how you arrived at this point?
On my local test site where I had some existing relationships and sample data I went to Toolset > Post Types, edited a post type which is involved in relationships, and changed the slug of the post type and saved.
I went to Toolset > Relationships and checking the existing relationships they appeared as normal.
Going to the post edit screen of one of the affected posts I could see the existing relationships, no problem.
And checking the database, in wp_posts I could see that the post_type had been updated with the new slug.
Can you clarify what order you did things in, i.e. defining post types, importing data, setting up relationships, changing post type slugs?
I'll need a copy of your site to investigate further to see if we can identify where it's gone wrong, and I'll set up a private reply for you to share backup files.