Sometimes I noticed that my community site language has changed, even when I don't actually change it. This usually happens when I want to view my projects via navigation bar. I do not even hover the language thing (globe icon).
Random language? "Catala" is related to your phone/computer locale?
Maybe you are using a "private mode" or some form of privacy shield ("hardened" browser, antivirus, firewall) and your preferences are wiped out at some point.