This may be a plugin problem. Please try disabling everything in Tools --> Addons --> Plugins, restarting Firefox, checking for the issue.

I disabled all the plugins; refreshed the browser and nothing changed. :s

Hm. Can you please try a new profile? managing profiles

It didn't work. However, I also noticed that the Unicode problem was also happening with Chrome. One of my friends is also having with this problem, also on Chrome. So this is leading me to believe that it might not be a problem with Firefox as I originally thought.

Try to toggle some of the Boolean gfx.font_rendering prefs on the about:config page to disable some features.
Filter: gfx

gfx.font_rendering.directwrite.use_gdi_table_loading

To open the about:config page, type about:config in the location (address) bar and press the "Enter" key, just like you type the url of a website to open a website.
If you see a warning then you can confirm that you want to access that page.
You can use the Filter bar at to top of the about:config page to locate a pref more easily.

Nothing changed.