Setting up multilingual nodes I am trying to set up a D8 (8.7.9 to be precise) multilingual site and hitting some weird bug.

I have a node type basic page consisting of the title field and a body text field.

Initially I create the page in German (title: "test page de" / content "test content de"), then click Translate to add an english version, save it. So far, so good - the german page pops up at /de/node/12, the english one at /en/node/12, the language switcher works fine.

Then, I edit the German page to say "test page de-1"/"test content de-1", and submit. The German page shows the proper content, as does the English one, but now, when I edit the English page, I suddenly get the title set to "test page de-1" and the body to "test content de-1". What is going on here?
Found the issue: I had the language detection under /admin/config/regional/language/detection messed up - content language detection was identical to UI language detection (which was User account first, URL second). Used URL only for content language detection and now it works.