Interesting; the title displayed OK minutes ago, on the main page, in Firefox/OSX. But now it's showing as unsupported-glyph boxes inside the page... but still

Interesting; the title displayed OK minutes ago, on the main page, in Firefox/OSX. But now it's showing as unsupported-glyph boxes inside the page... but still looks OK in the titlebar of the item (comments) page. Did some automated or administrative process mutate the characters? Or is this just Firefox drifting, in choice of font?