I'm afraid I do not know how to reproduce it. I was playing with Derek and Strannik, both of who, I think, have set MG to use languages other than english. There was also a german speaking player (Brainbug) who may have set MG to use german.lng. I, however, use english.
I launched the binary using the megaglest start script, as usual. This is a standard 3.5.0 x86_64 Linux installation.
Since I cannot reproduce this, let's ignore this issue until it happens again and we can find a way to reproduce it.