TYPO3 Core

It seems the context provided in AJAX is already wrong JSON.parse(JSON.parse(this.createRequestBody(t)['ajax[context]'])['config']) reveals the original instead of current language.
This is then returned from AJAX request and rendered within the form, leading to the value being submitted to DataHandler on save.

Our suggestion: Adjust the context to use the actual currently selected language.
Also on every update of the parent language, update all inline language values to match the parent.

I can also reproduce this with the other way around:

1. Create a content element of type textmedia
2. In CE, set to language -1, save
3. Add image (field "assets"), save
4. Set CE set language to 0, save
5. Now look at the entry in the DB, the entry in sys_file_reference will be with -1, the entry in the content element will be with 0
6. Now translate the element (connected mode)
7. Open the translated element: you will see 2 file reference, one of them is dimmed (this is the sys_file_reference=-1 one from the CE in orginal language) and one of them is the copied element.

And I think this is the same root cause as #88980 with the additional problem that in #88980 allowLanguageSynchronization is set to true and then the images in the default language are copied on translate.

You can find existing records like this:

select r.uid,t.pid,r.pid,r.sys_language_uid,t.sys_language_uid,t.header from sys_file_reference r inner join tt_content t on r.uid_foreign=t.uid where not r.deleted and not r.hidden and r.sys_language_uid=-1 and r.tablenames='tt_content' and r.sys_language_uid!=t.sys_language_uid order by r.pid,r.uid;

or just search for mismatch in sys_language_uid:

select r.uid,t.pid,r.pid,r.sys_language_uid,t.sys_language_uid,t.header from sys_file_reference r inner join tt_content t on r.uid_foreign=t.uid where not r.deleted and not r.hidden and r.tablenames='tt_content' and r.sys_language_uid!=t.sys_language_uid order by r.pid,r.uid;

Patch set 2 for branch main of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/87595

Patch set 3 for branch main of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/87595

Patch set 4 for branch main of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/87595

Patch set 5 for branch main of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/87595

Patch set 6 for branch main of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/87595

Patch set 7 for branch main of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/87595

Patch set 8 for branch main of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/87595

Patch set 9 for branch main of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/87595

Patch set 10 for branch main of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/87595