I know it's 3 month old topic, but, Opera sync used to work like a charm, I had all passwords from all devices, but last several months, my passwords do not sync accross devices. I used to login to a site from home, then go to work and login using the saved credentials... Now, no passwords sync. The only time it really synced lately, was when I reset the sync, which started syncing the "reset", meaning, each device that connected after the sync reset, "synced" and deleted the local data as well. letting me with a manual encripted couple months old backup.
The other issue is that it keeps syncing my open tabs from home to work (not the opposite) despite of me having tab sync OFF in ALL devices!!!