Weird "Shadow" from 100% Transparent object in Cycles on low bounces? I have the following Setup:



I disabled the Shadows for the Emission and Transparent Objects here



and set all bounces to 0.

Now I'm getting this weird artifact on the ground:

which is really suddle here but it has become a lot more noticeable in a more complex scene of mine.

If i set the Diffuse-Bounces up to 1 it is gone.
I tested the same thing with a Glossy Ground, here i have to set the Glossy Bounces to 1.

Why is this happening and is there a way to avoid it without having to increase the bounces?
Disabling also the Diffuse ray visibility on the transparent object removes the shadow without increasing the bounces. 

The effect is also reduced (without disabling Diffuse) when the World is completely dark, but not if the emissive object is larger than the transparent one.