Export Elev Grid -> Shelved/Blocky results

This issue has been happening for awhile, but since I do not normally export surface grids from GM, I've been to live with it... until now.
I'm working with LiDAR data and created an elevation grid (DTM). Everything looks great. When I export elevation grid as geotiff (and other formats), all of the vertical elevations are at even 1-ft intervals.
See image below. The blue line is the surface created by GM based on Lidar. The red line is the exported geotiff.
I need the exported geotiff to match the original.
FWIW, I see this same issue (even 1-ft intervals) on other projects with different source data resolutions.
I need the exported geotiff to match the original.
FWIW, I see this same issue (even 1-ft intervals) on other projects with different source data resolutions.

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Answers
When you export your GeoTIFF elevation grid, be sure to select the option to use 32-bit floating point samples. If you select either of the integer sample options, and use FEET for your vertical unit, the elevation values will be stored as integers in feet, and you will get the result you are seeing.
Cheers,
Bob