Date & Time: Since patch 5.45
Frequency: Always
World name: n/a
Character name: n/a
Retainer name: n/a
NPC name: n/a
Monster name: n/a
Class/Level: WHM, AST, SCH
Party or solo: n/a
In-game time: n/a
Area and coordinates: In any area where you can be zoomed out to max
Housing: n/a
Steps:
1. Equip or glam Makai Moon Guide's Gown as WHM, AST, or SCH
2. Zoom out in any area to the max
3. Cast any spell that makes the gown wave around, ie Medica, Cure, Physic, Helios
4. Observe the black flaps on the gown clip with the grey part of the gown
4b. Alternative just run around and observe the clipping

See picture for example
https://i.imgur.com/Ft4HtJV.png