I keep having this problem while doing a simple 3D visualization of my newly created DEM in QGIS via the threejs plugin.
I work in Balkan Zone 7 metric system and, when I try to visualise the DEM that I created from points (which were transformed in Balkan Zone 7) using the TIN interpolation method, I get a really, really tall 'church-spiral-like' column in my browser. I have to scroll all the way to the top just to see my visualization.
But, of course, if I change from metric to another CRS, I get flat terrain in my visualization while my threejs display's the following message:
The unit of current CRS is degrees, so the terrain may not appear well.
The problem doesn't seem to appear while working with free data like the ASTER GDEM or SRTM data for my country, no matter if they are set to WGS, Pseudo-Mercator or Balkan Zone 7, the topography and the terrain still appear well.