Why are my Rocks flickering on camera movement?

Hey there,

I have this problem where I build a rock cliff out of static mesh rocks (from the elemental demo) but when I shake the camera in viewport or in playmode the rocks start flickering (disappearing and reappearing again) all over the cliff.

I tried ctrl r but it did not help with the camera shake, only with a stable image when I don’t move and I set my graphics to forward lighting which didn’t help either.
Also someone said that not scaling the rocks huge would maybe help but in my case it didn’t.

Does anyone have an idea thats happening, and how to fix that?