Features in KMZ files generated from a map service do not honor the original ObjectID order.
Last Published: April 7, 2016ArcGIS for Server
Bug ID Number
February 13, 2015
July 28, 2020
ArcGIS for Server
After review by the development team, it has been determined that this issue is related to a known limitation with the software that lies outside of Esri's control. The issue's Additional Information section may contain further explanation.
KML output from server reads features in order it is returned from ArcGIS core.
The order may depends on many things - filters/extents/renderers etc. If users need a certain feature order they should specify a query filter using "ORDER BY".