Height depending texture issue

Hi!

I have imported a model to the “Cesium for Unreal Samples” project and as long as I keep it close to the ground level everything looks ok, but if I bring it all the way up to say 1000000 on the Z axis I start to get some weird texture and lighting artifacts. Please see the examples below:

Z: 0

Z: 1000000

Does anyone know how to fix this?