Some page is rendered partially in English and partially in Chinese
Sometimes (both on linux and windows, Firefox) it happens that pages are rendered with a different language from the one selected or in in a mix of language. It happened right now with the question Improving documentation. There is a screenshot for the issue.
I'm not able to give a recipe to reproduce this behavior, it seems to happen "randomly". The good news is that refreshing the page is enough to fix the thing.