Based on the documentation topic, I would expect all these translations to work, not only the German translation. So, I assume there is a bug somewhere that affects languages that have a different number of plurals than English.
I don’t know. German works fine, so I usually don’t see that something is broken. I only noticed because I used messageFormat for the first time yesterday and chose Polish for testing. The rewind chat section is hidden if there are not enough messages, so to test more than the “other” part, I wanted a language with multiple plurals.
I just tried a dev install based on the stable branch, and it seems to work there:
So I had really bad luck by choosing Polish as a language with a country code while I was testing, and if I had used Ukrainian everything would have worked without issues That would have saved me a lot of time.