[Act 2] Rathbreaker Non-Aggro AI Bug + Unkillable

Encountered a bug with Rathbreaker where their AI bugs out and they just stand still doing nothing. Attacking does nothing either - the damage shows on the HUD but the life bar never decreases.

Rathbreaker can still be stunned or poise-broken, or whatever the yellow bar is. Stunning/poise-breaking does not fix the bug, and they return back to their default position.

Steps I've done to replicate this:
1. Start the Rathbreaker fight.
2. Run down the hill, making them de-aggro and return to their initial position at full HP.
3. Go back up the hill to fight Rathbreaker.
4. Sometimes Rathbreaker re-aggros, sometimes this bug happens.

Happened to me just now. Tried singing out and back in, didn't help.

I have the same bug now 🤦🏻

Press esc, click respawn at checkpoint. That will reset the map.