HOW TO
Editing a z-enabled ArcGIS Online hosted feature layer fails with the following error, observed in a web browser's developer tools or Fiddler:
Error: 'add' parameter is invalid. The specified geometry is not in the correct format. Geometry does not have z-values Cannot not perform operation. Invalid operation parameters.By default, ArcGIS Online disables z-values on publishing a z-enabled layer as a hosted feature service.
Note: Even sharing a Web feature layer from ArcGIS Pro with the 'Elevation' property set for the z-enabled feature layer behaves identically.
If possible, publish the contents by uploading a zipped file geodatabase as an item to ArcGIS Online. This keeps the enableZDefaults property as true on the hosted feature layer. (This can be verified from the Update Definition operation available at Admin REST end directory.)
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