Strange black artifacts with movable light

Hello !

I recently switched to 4.15. And i have strange artifacts i didn’t have before in 4.14.
It happens both with the forward and deferred renderer and i tried tweaking settings but wasnt able to solve this problem.

Can anyone tell me what this is about ?
Thanks

I don’t think that’s a shadow glitch, kind of looks like maybe a mesh is too close to the camera and it’s clipping

Oh yeah…
One of the plugins i use was causing the issue. Thanks i first thought it was a rendering glitch…