Steps to reproduce:
Create 2 language, edit/translate them in both language.
While viewing page in default language - press "edit" to edit the page.
Edit/delete anything on the page
Select "Revert to last published version" option to exit edit mode
Change space language to the other one
Translate editor should be loaded correctly.
Confluence will show a pop-up "<Username> reverted to a previous version of this page" and redirect to an edit form for the default page.
Use "Close" button on exiting.