ISP/Type: Clearwire (4G Cellular Wireless Broadband)

Internet Connection Speed: 3-6Mbit

Date & Time: 6 Aug 2014, ~10:30pm EDT

Frequency: Once (Did not reproduce)

My Character Name: Olorin Bustyoas (Lalafell M)
Characters Directly Involved in Incident: Kisto Journe (Lalafell M) and Andy Fox (Hyur F)

World: Sargatanas

Class/Level: Kisto and I were WHM50, Andy was MNK50.

Area and Coordinates: Binding Coil of Bahamut Turn 5, at the edge of the battlefield.

Party or Solo: Full Party (8)

NPC Name: None

Monster Name: Technically none. We were preparing to fight Twintania & Co.

In-Game Time: Oh I have no idea.. sorry!

Steps: Kisto and I were re-buffing the party in preparation for another attempt to beat Twintania. The usual stuff - Stoneskins and Protect. Kisto tried to cast Stoneskin on Andy and it wouldn't let him - the cast would be interrupted as if the arena's barrier was active and he was outside casting on someone inside. He told us on our voice chat that he got the Aetherial Interference error message. I had seen this same problem before a few days ago, so I told Andy to run back up & out of visible range and come back. That fixed the problem.

As I mentioned I had seen this same bug a few days earlier in Syrcus Tower. I was buffing my party and it wouldn't let me cast on one of them. After a few minutes trying different things we figured out that having the person run out of range and coming back managed to 'fix' the problem.