I have a bug were gonarch just keeps running on a spot for about 10 seconds and can't take damage during that time. Any ideas what is wrong?

Its a known bug it usually happens if you shoot her too quickly before she turns around or shooting her in the wrong "areas" i think. I heard that NGHL client doesnt have this bug but i could be wrong.

Fastforward to 2:23 :

Check this video to see how I fight her to avoid it.

I was able to avoid the bug. I was shooting the first shot before gonarch had turned around. Thank you for the help