I was using Browsec VPN to connect to a UK server from the US. After disconnecting VPN my FB was in Cyrillic; the Russian-region alphabet. Following the reloading of the page, it appeared to clear... but now I'm going to be running diagnostics to make sure nothing untoward is happening after uninstalling the extension. Firefox 103.0 (64-bit) | Ubuntu 22.04 LTS
There's nothing to worry about. Most likely, someone used this IP with Cyrillic setting earlier, and FB remembered it for this IP. This situation is natural for VPN, where the IPs are shared between millions of users worldwide.
