Sigh ...
I dunno what am i doing wrong here.

I mean… the thread title mentions combat and you showed a picture of the combat log. I hope you can see how your message might have been misunderstood.
Your complaint shows the limits of using dynamic sound mixing to solve the looping voice problem. It works well with vendors, it’s middling for cutscenes as ExarchofJustice points out, it’s no use when you’re trying to focus on something next to a chatty NPC.