it's possible to edit objects in ezobjectrelationlist attribute of a content object with the following configuration in site.ini :

[BackwardCompatibilitySettings]
AdvancedObjectRelationList=enabled

In a multilingual install, the new version is sometimes created in a wrong language and others translations are archived (see steps to reproduce). I think it's because of the creation of new version in kernel/classes/datatypes/ezobjectrelationlist/ezobjectrelationlisttype.php:903 without any language in parameter.

Steps to reproduce

On a fresh multilingual install english and french with site.ini/[BackwardCompatibilitySettings]/AdvancedObjectRelationList set to enabled
1. add a "Related objects" attribute to the class article with Selection method set to browse, type set to "New and existing objects", allowed classes set to "article".
2. create an article in english
3. translate it to french
4. create an other article in french
5. translate it to english
6. create an other article in english and add previous articles in the object relation
7. check the checkboxes in the relations list and click on "Edit selected"

In the edit form, the first article is in french, the second one is in english and if you click on "Send for publishing", others translations are archived.