White flashes in viewport when changing material parameters?!

Hi guys!
Anyone experience this in 4.25…I get weird white flashes when I change a parameter in the instances of my materials. Its a white flash on the mesh that has the material and then it settles back to normal. I am using the exact same material in 4.24 side by side and there are no such flashes…any clues?

A solution I found is to turn lights to movable which sorts the issue out and back to static…?!