I have a multilingual setup, and the content translation works well and smooth.
But when I try to edit a node on the other language - I have the same link from the content admin menu, which renders the default language form. I.e. I have /node/21/edit both for En and De versions.
For the test I've try to alter the node object on the form build step (couldn't found a correct hook, so just try it in the FormController::getContentResult() ) - no luck:
$translated = $form_object->getEntity()->getTranslation('de'); $form_object->setEntity($translated);
form object states the active language as 'de', but the rendered form still has en version fields.
Also the form has native language switcher (Languages), which in my mind should do language switching, but for me it shows only English and does nothing.