Not able to Target, Damage or Hit a Boss

During a tier 15 Map Boss encounter (the Big Bird with the Bell that runs away), I started the fight without problem, but when the bird got down to about the 70% health mark, where it would normally run and get the bell, it just didn't. And at that point I was no longer able to target it with my melee attacks or damage it with my lightning spears thrown at it. I invited in another player to see if he could help, but he could not hit/target/dmg the boss either. I even let it kill me and revived at the check point, but again, I got it down to the point it should have run and gotten the bell, but it did not and the was immune again.

I do not recall the specific attributes on the waystone I used, but it was modded for all rare and magic creatures with the omen that does that sort of thing.

Anyway, thanks for a great game and I can't wait to see the rest!!!

It's a Known Issues, which also post at the top thread of this forum by GGG.

So this is a Known-Bug since Dec 2024.
Avoid the Blooming Field map which with the boss (Black Crow).
*Blooming Field map without the boss is fine.

Start another map if you see this boss.

Using Leap Slam (Mace) can leave the gate (no need to drop XP to leave).