Light reflection flickers with voice motion

Hi…i have a strange, but kinda cool effect on this animation
Important Words - Version 2020 - Download Free 3D model by Miguelangelo Rosario (@miguelangelo2k) [9762183] - Sketchfab
the light reflection is flickering with the voice …
anybody with an idea why ?

I can’t reproduce that here, can you provide more information please?

Hey Bart…will grab a video…i have the same effect on this model

its a nice effect, was just wondering why this is happening