CKEditor Link Plugin breaks media library in modal

Hi,

we try to use the following setting:

- media entity "image" has a text field "copyright", where a CKEditor is used with a link button
- a node entity has media field referencing media entities of type image, the form widget is Media Library
- when I upload a new image I can edit the media fields within the modal of the Media Library. Here I see my copyright field. When I click on it the whole modal is filled by the fields for link plugin. When I fill in the fields and click "Save" nothing happens
- to show how it should work: when I click on the table button for CKEditor the form for this plugin does not replace the whole modal but it opens a new one named something with cke_

I have no glue where to go deeper into it - maybe someone with some more experience with the CKEditor can help?

Best,
Tobias