So I've noticed this problem after I upgraded from Ubuntu 13.10 a few days back. I've noticed that whenever a window title is supposed to contain any accented character like "ï", the title bar replaces the character with a box

Notice that "Daïa" is displaying correctly inside the window but not on the title bar. Also, this problem only appears when the window in question is not maximised. Upon maximising the window, the character renders correctly.
My question is, why is this happening and how can I fix this? Is this a bug? I'd appreciate any advice. Thanks.