I suspect its a font cache issue. Let's try this:
Close all running applications. Open the Terminal app and enter the following command. You can also copy/paste it from here into the Terminal window:
sudo atsutil databases -remove
Terminal will then ask for your admin password. As you type, it will not show anything, so be sure to enter it correctly and hit enter/return.
This command removes all font cache files. Both for the system and the current logged in user account. After running the command, close Terminal and immediately restart your Mac.
If you have Font Agent Pro
Open FontAgent 8.
From the menu bar, select FontAgent > Preferences.
Select the "Caches" tab.
Select either "All users on this machines" or "This user only", then select "Clear caches now"
Restart your computer.