The address book used here has several contacts that contain the fore and surname in the "Last:" field of a contact. When the forename is removed from the "Last:" field, then put it into the "First:" field and the "Edit Contacts" Dialog is closed, the sync-progress bar appears in the lower right of the Thunderbird window. Unfortunately it does not progress. It just sits there idle.
After closing Thunderbird and starting it again, no contacts are being synced anymore and the progress bar does not appear after changing contact information.
The remote address book has to be removed and then re-added in order to make the connector work again. After re-adding the remote address book the previous change is missing.

When adding a picture to a contact, the connector behaves the same.