Strange rendertarget cubemap issure

Get Some strange issure with cubemap render taget.

Render Target sizeX set to 1024 (if i set 512 or less or set big screen resolution (1920x1200) issure are missing)

I create second UWorld and render scene to there. When i spawn actor with USceneCaptureCube component and set result cubmap to the skybox in Main visible scene.