Letters randomly vanishing from chat box

Time: 9:30PM EST, 2:30AM server time
Frequency: Once
World name: Gilgamesh
Character name: Tsutsuki Tsuki
NPC name: n/a
Monster name: n/a
Class/Level: n/a (Alchemist lv50)
Party or solo: n/a (solo at the time, talking in FC, but was effecting everything in the chat window)
In-game time: n/a
Area and coordinates: The Goblet
System: PC
Steps:
No real steps, just certain letters vanishing and being replaced by spaces, starting with the letter f, slowly spreading to other letters. As I typed the letters would instantly be replaced by spaces, as if the font data itself was a space for those letters. Attempting to exit game resulted in a crash to desktop, relogging fixed it.

http://puu.sh/dNhva/37e5280576.png
^ Image showing what it looked like