Frequency: Every Time
Class/Level: Red Mage/Any Level
Steps:
1. Equip a Red Mage Weapon
2. Draw the equipped Red Mage weapon
3. Use the /changepose emote

Every time the Red Mage weapon is drawn and the /changepose emote is used to start the idle animation, when the left-handed portion of the weapon reaches the peak of its lift and begins to descend, there is a small jitter in the animation. I can only speculate that there is something wrong with the animation curve at that point.