Dynamic Lighting flickering

Hello. I have this strange issue, I can’t understand why my dynamic lights make materials flickering.

It only happens with wet materials, and temporal antialiasing will fix it, but I need to fix it with the FXAA too. Someone can explain this issue, and if possible, give a solution?

Thank you very much

I am also having a very bad issue on character lighting… when character walks through a light this happens

1482589613d8173f90000fe07af6e6fd2144bb44.jpeg

You have stumbled on one of the reasons why UE4 uses temporal AA, shader/specular aliasing.

Simply put, those pixels which flicker have normal in which reflection points directly to our lightsource and you get very high spikes of brightness.

This should give nice overview and good starting point on ways how to reduce specular aliasing in shader.
http://blog.selfshadow.com/2011/07/22/specular-showdown/

Also interesting little presentation from this years GDC.