Sync-Enabled Feature Service With Archiving Seems to Download Full Dataset on Sync

[EdwardBlair]

We're experimenting with use of sync-enabled feature services to support a mobile application.  We're using archiving as opposed to versioning to detect changes.  In a simple test I added a new feature to the parent feature class in the enterprise geodatabase to see if it would sync down to the client (a runtime geodatabase on a laptop).  Eventually the new feature showed up on the client -- which is good.   However, I noticed that ALL of the features in the runtime gdb had the same gdb_from_date value as my new feature.  I would have expected my new feature to have a layer gdb_from_date than all other records.   Which prompts my question, what/how much information is actually transferred to the client on a "sync"?   I thought it would be only the changes since the last "create replica" or "sync replica" operation.   But it seems like it might be re-sending the entire dataset.

Any insights would be much appreciated.

[EdwardBlair]

I've learned a *little* more about this behavior, but still don't understand it.  We've found that when we follow similar steps in ArcPro (download the mobile geodatabase, make updates in Pro to the service, then sync to the mobile geodatabase) that the gdb_from_date was only updated for features that actually changed.  Which is different than the behavior we see when a sync is performed using the runtime API.  

So, I guess this is a little more data, but not more knowledge.