Harvest Tier 4 Bosses' phase transitions are consistently delayed regardless of DPS

Hi GGG team,
I am writing to report a serious issue with the phase transition timing of Harvest Tier 4 bosses (Ersi, Janaar, Namharim).
Currently, these bosses often stay in an "invulnerable" state for an excessively long time before moving to the next phase. This issue occurs regardless of the player's DPS. Even when the damage is moderate, the boss frequently stands still while immune to damage, failing to initiate the next pattern (like burrowing or summoning adds) immediately.
Currently, players have to manually stop attacking or move far away to force the AI to "re-recognize" the state and trigger the next phase. This is not a "reward for high DPS" issue; it is a fundamental problem with the boss's AI script and transition priority.
Key Problems:
Unresponsive AI: The boss stays immune but does nothing, wasting the player's time and Harvest buffs.
Clunky Mechanic: Having to "wait" or "move away" for a boss to function properly is not a normal gameplay experience.
Requested Improvements:
Please make the phase transition (starting the next animation or summoning adds) a top priority trigger that happens the instant the HP threshold is met.
Ensure the boss does not remain in an invulnerable but "idle" state for more than a second.
This inconsistency makes the Tier 4 Harvest encounters feel buggy and frustrating. I hope to see a fix that ensures smooth transitions.
Thank you.

P.S. I am using an AI assistant to help translate this feedback as English is not my primary language. Please understand if some terms are overly formal, but the issue described is a genuine bug I am experiencing in-game.