Xesht Bossfight - Portal Attacks cannot be evaded with Acrobatics allocated

My character has Acrobatics allocated and 6250 evasion which translates to ~66% evasion chance.

I was fighting Xesht two times today and in both fights his portal slam attacks hit me twice in a row, which shouldn't be possible with the evasion entropy system in place.

Here is a timestamp to a video where he does the attack and hits me:

https://youtu.be/cPWQRlblta4?si=E9resYTREZFUf4vW&t=256