If you are dealing with Georeferenced data to build elevation models, then please read this article to prevent errors in Elevations
Best Regards
Thanks for bringing this to light! I thought this was just an issue affecting the South African coordinate systems. I'm sort of relieved knowing everyone is in the same boat
After years of telling my colleagues it's best practice to work with coordinate systems if you're working with coordinated data, I'm now telling them the opposite.