[sam7]

I tried rendering a scene with a orange blurry glass in front of an emitter.

while figuring the correct settings I found this:

The glass with attenuation distance set to 9mm


The glass with attenuation distance set to 10mm



I tried lowering the light intensity but it still seems a littel strange to me.

Here is the scene if someone wants to test: Scene


[EDIT]

I'm getting a comparable incontinuity problem when switching from Roughness 99 to 98,99