Strange Shadow Bug on 3D Template

Hey, we try now some days to fix a Bug with the default 3D Template, this bug don't exist in the HD SRP only in the 3D Template.

I looks like the Shadow is changing when the Camera is a little Moving in a unnatural way
Here an example:


Any suggestion what we can try to solve this problem?

The Directional Light is not moving and the camera just moves around 0.001 per frame, i really have no idea whats the problem there...