POE2 Missing Viper Napuatzi in Utzaal

I just went through Utzaal, I got to the part where my quest is "Travel to Aggorat" after finding the stairs to Aggorat but Viper Napuatzi wasn't anywhere in the area, went and fully cleared the area, nowhere to be found, it worked properly when running through second instance but what was the first one? Why wasn't the boss, which is supposed to be there and necessary to progress there?