Platform:
Windows 7 Ultimate x64

ISP:
ATT

Type of Internet Connection:
DSL

Internet Connection Speed:
6mbps Down, 1.5mbps Up

Date & Time:
Various

Frequency:
About half the time

Character Name:
Pooka Pucel

Race:
Lalafell M

World:
Besaid

Class/Skill Rank:
R50 LNC / Happens any job/rank

Physical Level:
50

Area and Coordinates:
Adventure Guild Retainer Bell

Party or Solo:
Party and/or Solo

NPC Name:
Retainer Bell / Either Retainer

Monster Name:
N/A

In-Game Time:
Various

Steps:
1.) Summon Retainer
2.) Select Retainer
3.) Exchange Items
4.) Attempting to move up/down using controller D-Pad or arrow keys to navigate retainer inventory works fine
5.) Attempting to move up/down using controller D-Pad or arrow keys to navigate personal inventory works fine
6.) Returning to Retainer Inventory, can no longer use D-Pad or arrow keys to navigate up/down, but personal inventory works
7.) Once this happens, you can not go up/down in retainer inventory until exiting retainer screen and re-entering
8.) Happens about 50% of the time, not always right away, sometimes after exchanging items, sometimes after just browsing personal inventory
9.) Can not figure out a specific trigger for it, seems to be random.