That's interesting! I have a feeling it has to do with that ù, I'm not sure if the chat box supports special characters like that. I'll take a look at it, although I'm not sure how to type that into the game, my keyboard doesn't have that character.
this bug appears to happen with those ACII characters
you can recreate it by doing: alt+ (numpad x) as far as I know, I think these are unsigned shorts (16bit) so don't put in a number over 65535 or overflows yadayadayada computer stuff
etc Alt+0256 to do: ö.
ive tried with alt+246, erase it and blu screen with that UTF-8 bug(also to do a ù do alt+151, handy chart here http://www.irongeek.com/alt-numpad-ascii-key-combos-and-chart.html )