DTTG 3 sync: two ways to force it, one not working

I’ve set up DDTG/DT to sync via WebDAV. That works fine in principal.

However, today I noticed on my iPhone that it hadn’t synced in the last 10 days at all (Settings/Sync Locations/click on WebDAV, all databases in the list were synced 10 days ago). Apparently sync was set to “manual”.

There’s a circular arrow at the top right corner of the database list that I took to mean “force sync”. When I click on it, I get a daisy wheel for about half a second but the times for last sync do not change.

However, when I click the cloud icon on DDTGs main page, the sync is forced.

Question: What is the circular arrow for? If it’s intended to start a sync, that’s apparently not working (at least not for me).

In the preferences after tapping the sync location? The button just refreshes the list of remote databases.