Elevation surfaces in ArcGIS Pro are always multi-LOD, and Pro will display a lower LOD of the elevation surface from greater viewing distances. This is done to conserve resources as a 3d view with a long camera angle can have quite a bit of terrain data in it (several million triangles).
That said, we do tune the terrain system at each release to attempt to improve the appearance and LOD selection logic to balance between speed, resource consumption, and appearance.
In fact - we're working on enhancements in the next release (2.6) that will improve the resolution in constrained views (such as a case where you only have one DEM for a small area displayed, or when you have your view clipped to a specific extent) such as the one above.
One workaround for this in the meantime is to use the Raster to TIN geoprocessing tool to create a TIN Dataset of the same area, and use that instead of the elevation raster. TIN datasets always display at full resolution, and therefore should give you consistent elevation on which to place your buildings. The downside of this is that of course you cannot show a much larger area before resource constraints kick in again, but it should get you around this challenge. Another downside of this is that you can't publish a TIN dataset in a web scene.
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