The bug

When trying to load a minecraft.net page with an incomplete language code, like for example en instead of en-us or de instead of de-de all occurrences of the incomplete language in the URL are replaced instead of only the one specifying the language.

How to reproduce

Try to load for example https://minecraft.net/en/tent
→ It loads https://minecraft.net/en-us/ten-ust/; the "en" in "tent" was replaced by "en-us" as well