T9 Savage Debris Burst is bugged

Occasionally, when two comets are placed too close to each other, the subsequent wipe mechanic will not work. You see the damage, but do not actually take any.

Time: 8:30PM ST - 10:15 ST
Frequency: Occasionally
World name: Shiva
Character name: Sove Stellarum + rest of the party
Monster name: Astral Debris
Class/Level: WAR 50
Party or solo: Party
In-game time: Don't remember
Area and coordinates: The Second Coil of Bahamut (Savage) - Turn 4
Steps:
1. Place two comets too close to each other so they blow up
2. Occasionally, you take no damage but damage numbers still show up and it shows in combat log ("You take 18637 damage.")

Rest of the tempate is irrelevant, all party members were affected.