What happened?

Description

I have a blog channel with a blogType entries field that references a channel called blogpostsTypes. Whenever I try to save that field, I get the following error messsage

Blogposts Types is not a structured source. Only structured sources may be used when relating ancestors.

I don't quite understand the error message itself, this is a simple relation between each blog entry and an entry from another channel. Cannot find anything obvious related to that error in the logs, nothing in the console either as far as I can see.

The problem seems to lie with the field. I have tried to uncheck Blogposts Types and to check any other source in the "Sources" checkboxes and I get the same error.

Partners is not a structured source. Only structured sources may be used when relating ancestors.

Steps to reproduce

Cannot provide exact steps here. It's a craft 4 project that has been upgraded to Craft 5. It is a small client project that I have been using to test the fields CLI merge tool and the likes. A few fields have changed back and forth between dedicated fields and instances but not that field specifically.

Expected behavior

I should be able to save the entries field and update the number of min and max relations, which is why I edited the field originally.

Craft CMS version

Craft Pro 5.4.0.1

PHP version

8.2.22 (DDEV)

Operating system and version

Linux 6.6.26-linuxkit (DDEV)

Database type and version

MySQL 8.0.36 (DDEV)

Image driver and version

Imagick 3.7.0 (ImageMagick 6.9.11-60)

Installed plugins and versions

• CKEditor 4.2.0