When I am playing in any overworld zones (Sea of Clouds, Black Shroud, ect.) I am unable to see any NPC Dialogue boxes when I speak to them. The text does appear in my "Event" chat log and I am able to click through the text to progress it. This does not occur in cut-scenes or instances. I have confirmed that this is only happening to one of my characters which is listed below.

ISP:
Time Warner Cable.

Type of Internet Connection:
CATV

Internet Connection Speed:
10MBPS Downspeed

Date & Time:
Started around March 2016. I noticed it happened after a period of in game lag.

Frequency:
Always, it is constant.

World:
Balmung

Character Name:
Nazgar Bloodbane

Retainer Name:
None, although retainer chat boxes also do not appear.

NPC Name:
Cannot remember, I believe it was an NPC for the little ladies day event.

Monster Name:
None

Class/Level:
Warrior, level 60.

Party or Solo:
Solo

Race:
Race of your character when the issue occurred.
Au Ra (M)

Thank you very much for any help you can provide.