Date & Time: 5:50pm ST, 14th August 2019
Frequency: 2
World name: Jenova
Character name: Yotsusu Miku
Party or solo: Solo
In-game time: 5:20pm
Area and coordinates: Limsa Lominsa Lower Decks
Steps:
1. Affix a Heaven's Eye VIII materia to gear that forbids advanced melding
2. Affix a Heaven's Eye VI materia to the same gear
3. Log out
4. Log back in

Upon performing the steps above, the materia which should have appeared with the VIII materia on top and the VI materia below are now reversed, with the VI materia on top and the VIII materia below. This has occurred on two pieces of gear (as I explicitly made sure to meld the VIII materia first so that I could later easily replace the VI materia).

It is possible there are missing steps, as I did not notice this issue immediately.