Issue:
Completing certain objectives in the Summoner main quest causes the left D-pad slot to change to Advanced Materia Melding everytime the small cutscene for learning a new skill is triggered. I've only noticed this using the controller input.

Date & Time:
October 25, 2013 1:54 EST

Frequency:
Always

Character Name:
Eight Corova

Race:
Miqo'te F

World:
Sargatanas

Class/Level:
Summoner 40

Party or Solo:
Solo

In-Game Time:
10:40 pm

Steps:
-Complete main summoner story objective
-Learn new skill
-Slot changes

I've attached a screenshot showing the icon