It looks like if a carriage return is following the two "S"... Yet, I am not able to reproduce it here...
Not if you installed overrides in a skins/ directory, alongside the user_settings/ ones (which location depends on the OS)...
If you have another user account on your computer (or can create another), try from it and see what happens...
The log file might also give clues (e.g. with the fonts loading messages).
You could also try with another language setting (on another user account, to avoid messing up yours).