@daxorp Yes, There is a flag for testing in desktop version but, at least for now, it causes more trouble than it brings benefits because it will take a long time for sites to start changing it.

And I still think that It has nothing to do with privacy or security.

So it's been 6 months since opera answered this issue, now I have the same problem and can't find a solution anywhere. For me it only happens on "op.gg", it happened before like for Barkuti when clicking on email links but i didn't give much attention since it stopped by itself. But for this specific website the problem kepps happening. Like srsly it seems to be a very very old problem this browser has, it's a real shame that you haven't fixed that yet.