What happened?

Description

I have a nested Matrix which will throw the error "The owner element must be a derivative." sometimes. It happens when we edit elements in a slideout.

When it occurs, it will prevent us from saving. The only workaround is, to open the slideout content in a new tab and save there. Or to save the owner entry, but this will delete the content of the edited child. Then the element can be edited again. We have several nested Elements (Accordion, Column Text, ...) and it happens on each of them.

While developing locally I think I got it once, but on servd it shows up a lot. To me (admin) and all of the authors.

I could not find a safe way to reproduce it. But I just have to create some nested elements and after some time it will happen.

Steps to reproduce

1. Create a nested matrix element
2. In the content, add children, tinker around with editing/saving until it occurs

Expected behavior

No errors should show up when saving nested elements.

Actual behavior

"The owner element must be a derivative." shows up occasionally and prevents saving. Here are two examples:

Craft CMS version

Craft Pro 5.6.1

PHP version

8.3.8

Operating system and version

Linux 6.10.14-linuxkit

Database type and version

MySQL 8.0.36

Image driver and version

Imagick 3.7.0 (ImageMagick 6.9.11-60)

Installed plugins and versions