T10 undersized Wild Charge on maintank?

Type of Internet Connection:
DSL

Date & Time:
Friday 15/4/2016 and Saturday 16/4/2016 handful of times

Frequency:
Sometimes


World:
Cerberus, Instance Server for T10/Final Coil of Bahamut Turn 1

Character Name:
First tries Friday:
Sigurd Demizar (DRK)

Second Tries Saturday:
Aelia Sokoto (WAR)

Retainer Name:
None

NPC Name:
None

Monster Name:
Imdugud

Class/Level:
WAR/DRK 60
(Party 1: Aelia Sokoto SCH; Asny Rak'nys BRD; Sigurd Demizar DRK/// Party 2: Asny Rak'nys WHM; Sigurd Demizar SMN; Aelia Sokoto WAR - all classes each 60)

Party or Solo:
Party 3 man

Race:
Elezen M (Sigurd)
Au Ra F (Aelia)

In-Game Time:
---

Area and Coordinates:
Final Coil of Bahamut Turn 1 Bossroom

Housing:
---

Steps:

- Doing all Coils Unsync for/with friends in 3-4 man parties
- Queueing T10 as 3 man party
- In P3 (after first adds) Wild Charge randomly targets the maintank making it impossible to "share" the damage and killing the tank

Having done this fight lots at level 50 I am sure it never targeted any tank.

That's not a bug.

With only 3 people, the usual targeting algorithms don't apply. You would see this same behavior back in the day if 5 party members were dead