Available with Standard or Advanced license.
The Geometric function used in the mosaic dataset item does not reference a DEM.
Some satellite and aerial imagery can be orthorectified to adjust for distortions due to elevation using the Geometric function. This function uses the sensor's transformation definition and a terrain model.
There are one or more Geometric functions associated with your mosaic dataset items that do not use a DEM. A DEM will result in a more accurate image.
Make sure there is a DEM specified within each geometric function.