Invincible boss does not enter phase 2

Boss invincible after reaching half HP, but still does damage.
Does not start another phase, just still chases me.

Tried few times.
I did restart game too.

https://drive.google.com/file/d/10yRYLk6yU0Mk_yNqSYP4kJdWXNkZKfWW/view?usp=sharing