So, I am responding to my own post. If you have OS version version 188.8.131.52 (platform 184.108.40.206) kernel v. 220.127.116.11 like I did, you should also have this caller id font bug.
The solution is to upgrade your OS. Follow this link to another post on this forum: http://www.blackberryforums.com/viewtopic.php?t=1652
Note that the OS upgrade is to 18.104.22.168, not .142. It is a must-do, however, since it also fixes the speakerphone bug and possibly others. Read the whole thread before installing.