Are you referring to the different level of detail on the big wall in the distance?
If so - this isn’t a bug - rather the Level of Detail (LOD) system in action. The LOD system allows the game to have longer draw distances by reducing the # of voxels drawn.
Sorry - yes - that is an issue. The heuristic code that is generating the LODs isn’t quite smart enough to deal with a few cases when the different LODs meet. This issue can often be extremely obvious within caves - and you can see gaps into the open air.
So this is a known issue - but not currently a high priority to fix.