I have noticed this problem occurring when I try to import rasters into Google Earth Pro from ArcGIS Desktop 10.4.1. I can take a 1/3 arc second resolution DEM and it looks great in ArcGIS until I use the layer to KML in which case it changes the resolution to something strange.
When I measure the pixels in Google Earth, it's about 150 meters per pixel side where it's only 10 meters in ArcGIS. I have played around with exporting at a higher DPI and a 2048 size of returning image. Anyone have any ideas on how to get a DEM into Google Earth in its native resolution?