When trying to create a map tile package in Pro 2.3.1 I'm running into a "Layer type is not supported: layer name" error for a cached map service. I can't run it via the geoprocessing tool as it hangs so I'm using the Python window. I've tried both an ArcGIS Online basemap and a locally hosted cache map service (configured for allowing clients to export 5mil cache tiles). Both basemaps I can use the 'Download Map' tool with to create a tpk but that limits the scales for a given extent - which I thought was due to the number of tiles to export setting but appears not to be - so I can't create a tpk with the extent I need with all the scales.
Why does Download Map (to create a tpk) work with the same layers which the Create Map Tile Package doesn't support?