Mechanics Question: Machinist - Rook Auto-Turret

[Rongway]

Did tests.

Solo. Sight aggro A. Sight aggro B. Turret does not attack.

Solo. Attack-claim A. Sight aggro B. Turret attacks A.
--Targeting B, no auto-attack. Turret does not attack B when A dies.
--Targeting B, AA active but still not auto-attacking because Gauss Barrel. Turret does not attack B when A dies.

Solo. Attack-claim A. Attack-claim B. Turret attacks A.
--Not targeting B, turret attacks B when A dies.
--Targeting B, turret attacks B when A dies.

Party. Not targeting A. Party member attacks A. Turret does not attack A.
Party. Targeting A. Party member attacks A. Turret does not attack A.
Party. Not targeting A. Party member attacks A. Turret does not attack A. A hits turret with AoE. Turret attacks A.
Party. Not targeting A. Party member attacks A. Turret does not attack A. A hits MCH with AoE. Turret attacks A.

Party. Not targeting A, not targeting B. Party member attacks A and B. Turret doesn't attack. A hits turret with AoE. Turret attacks A.



Conclusion
The turret will not attack anything that is not in the enemy list, no matter what you target. If you perform no actions, the turret will attack the earliest enemy on the enemy list.

This means the turret will not attack unless one of the following is true:
--you performed a hostile action on the enemy.
--you buffed or healed someone who is already engaged with the enemy. (Due to the actions available to MCH, the only way this is possible is if someone else first heals or buffs you, then you buff yourself)
--you activated Promotion, causing your turret to buff someone else who is already engaged with the enemy.
--you or your turret were hit by an AoE.
--the enemy is a raid boss.

Raid bosses are automatically added to everyone's enemy list as soon as one party member engages, but standard bosses follow the same rules as normal enemies. This is why a turret will begin attacking a raid boss without any MCH input.

However, the earlier mentioned scenario where the turret begins attacking after a BLM begins casting cannot happen; someone else must have engaged the mob before the cast finished.