…any advices? The material was slightly darker before this happens and to be exact when I change it to something different (tried the orange from the other side of the light) the problem is gone so looks like the colour is a problem but why???
Hi, my guess is that you accidently duplicated the geometry - sellect the problematic lights and move them somewhere else and see if there is no duplicate in the same place.
My second guess is that you have wrong settings of Alpha Threshold. You can find it in RenderLayers settings - under Passes - Alpha Threshold - try to change in in both directions, it might help.