Kabala Cruel - immortal for 2 minutes

So, the fight goes as usual, then she somehow BUGGED into top upper area.

She has like 1 cm red life and full energy shield.
For whole 2 minutes +- I cannot damage her, no matter what I do.
I threw grenades there which has large AoE, shoot , nothing.

I was so close, to reload whole battle.
Then I "touch her" and she unbugged.