Everything is fine with Sync in desktop Opera at the moment at least for me here in the U.S. Still having an issue or are things working fine now (including Flow)?
@Spacey42 At https://www.google.com/preferences?#tabVal=1, there's a "Results in new window" option. A few weeks ago, some users were having issues with that setting where it was off, but Google was behaving like it was one. Users had to enable it and then disable it again and that fixed things. I think some were able to goto the URL opera://settings/content/all, type google.com in the search field and click "Delete displayed data" to fix it too.