New problem with Dropbox syncing

I have DevonThink Pro installed on two computers (MacBook and iMac).
I have set up Dropbox syncing as recommended. I do not have my DT databases stored on Dropbox. I have unchecked the DevonThink folder in Dropbox advanced preferences.

Syncing appears to be working, but each time I synchronise on my secondary machine (iMac), the process takes a long time retrieving files. It appears to retrieve the same files each time I sync, even if there have been no changes. For example, if I sync on my iMac, and then sync again without making any changes on my MacBook, this process of retrieving files occurs again.

Is there a way to avoid this problem?

Just to add a little more information.
I have just synced my database on the iMac again and, once more, it spent about 30 minutes retrieving dozens of records (I had added just one record to the database on my MacBook). I immediately synchronised again, and it is once more retrieving large numbers of records.
My database is quite large, 1.4GB.
It would be useful to understand why the synchronisation process repeats the retrieval of records each time I sync.

Please try the Sync operation again AFTER following these instructions…

To enable logging, type the following in /Applications/Utilities/ and restart DEVONthink:

defaults write com.devon-technologies.thinkpro2 DTSyncDebug -bool YES
defaults write com.devon-technologies.thinkpro2 DTSyncDebugHigh -bool YES

This will log more detail to your system log, which can be viewed in /Applications/Utilities/

After you’ve attempted the Sync, open Console, type “DEVONthink” in the filter field in the upper right-hand corner, and copy and paste ALL of the window’s contents into a new text document. Start a Support Ticket at our DEVONtechnologies Support Ticket System and attach the document to your reply. Thank you.

Many thanks. I will do that.