The Create Replica function facilitates synchronization. ArcGIS Hub uses the Create Replica function to update the cached version of the Open Data item sources, this enables up-to-date downloads on the Open Data site.
Image 1ESRI documentation recommends the Service Directory is disabled. This blocks all html requests, because the Create Replica function is an html request Hub cannot synchronize, this then causes an error on the Open Data page when attempting to retrieve files using the download option (see image)
An example on our own Open Data site is NPDC GeoHUB - Notable Trees
This idea submission is for ArcGIS Server to provide a special provision or alternative solution where the service directory can remain disabled while the Create Replica request/function can be successfully completed.
This would restore functionality to the Open Data product while still maintaining a disabled Service Directory without any need for a workaround or enabling the Service Directory unnecessarily.