I'm experiencing weird behavior when using the "Layer to KML" geoprocessing tool in ArcGIS Pro 2.0.1. The scenario is as follows:
I created a group layer (States) with 4 child layers corresponding to regions of the country (Northeast, South, Midwest, West). These region-specific child layers depict a different subset of content (polygons) from a shapefile of all the states -- I'm using definition queries on each child layer to control which features are drawn in which layer (my definition query is based on a field named "region"). The child layers use a Unique Values symbology, with colors based on the same field as the definition query ("region"). So, the Northeast states are one color, the Midwest states are all a different color, and so on. When I export the group layer to KML and view in Google Earth, all the states (across all the regions) are the same color. This isn't what was intended.
It appears that the KML file created by ArcGIS Pro has placemarks that all reference a style called "PolyStyle00". But, towards the bottom of the KML file, I see that "PolyStyle00" has been defined / redefined multiple times, with different fill colors. I think what needs to be happening here is that the KML file should have a few different styleUrls, such as "PolyStyle00", "PolyStyle01", etc, and the placemarks in each region should be referring to the appropriate styleUrl.
I think this is probably just an ArcGIS Pro bug, but if anyone can confirm, that would be great. Thanks.