Artefacts: dynamic lighting - persistents blacks spots in shadowed areas


I have some artefacts on the shadows in penumbra from distants objetcs.
When I move, there is persistents (fews milliseconds) black large spots behind the objects on shadowed areas.
My english is not enough good to well explain what’s the problem is, so you can watch this short video:

Black spots remains behind the tree after moving:


My light is dynamic :
Dynamic Indirect Lighting ON
Cast dynamic shadows ON
Cast static shadows OFF
Ray Traced distance field shadows ON

In Project Settings: Generate Mesh Distance field is ON

UE : v4.10
Asus GTX960

Thanks by advance

It seems to be related to movable skylight, but I can’t find the parameter or value that prevent this artifact.

Any ideas?