A Distributed Collaboration should synchronize Item details on the guest Portals, not just the data from the feature service, web map, file, etc.
A Collaboration will create a new item on the guest Portal and it will have the same Title, Summary, Description,Terms of Use, etc as that of the source item on the host. However, if any of those things change on the Host item, the Collaboration does not recognize it as a change.
The Collaboration should sync the Item, not just the Data that the item references. This would be especially useful when using a By Reference workspace in which the Guest Portal item is using the same data service as the Host item.