Boss of Blooming Field Map End Game

Hi everyone, has anyone encountered the case where the Boss of Blooming Field Map End Game becomes immortal and cannot be killed?

I encountered this case 3 times, the only solution is that I revive and start over. It's so bad that I lost 30% experience when I was at level 97 :)

I encountered this case when the Boss was in the middle stage, the Boss became angry and did not return to normal + used the bell to break the door.

Also I encountered a case where the Ritual did not close when I killed all the monsters. I wandered around for about 5' looking for something but no, I realized it could not close...