@KlausFranbrau2 It is not advisable to run on old versions, except for testing. Just too many potential security problems.
I don't know if I have any real information, beyond a couple of pieces: 6.1 is supposed to work fine, 6.2 is supposed to have issues, and there was a chromium update to 116 a few weeks before 6.2 was released.
6.1 Final is https://vivaldi.com/blog/desktop/6-1-rc-2/
First 6.2 snapshot was https://vivaldi.com/blog/desktop/catch-up-vivaldi-browser-snapshot-3054-3/
The snapshot before default enabling Portals was https://vivaldi.com/blog/desktop/another-round-of-fixes-vivaldi-browser-snapshot-3060-3/ [1]
The last 6.2 snapshot based on Chromium 114 was https://vivaldi.com/blog/desktop/same-old-new-window-now-opens-faster-vivaldi-browser-snapshot-3062-3/ , which is also the one that enabled Portal windows by default [2]
The first Chromium 116-based snapshot was https://vivaldi.com/blog/desktop/macos-geolocation-and-customizable-address-suggestions-snapshot-3070-3/ [3]
6.2 final was https://vivaldi.com/blog/desktop/6-2-rc-2/
Of these, the ones I tagged [1], [2], and [3] may be the most likely regression points. Given that Portals was an Experiment, it is possible to enable it in [1], and AFAIK disable it in [2] and likely for a while longer.
While determining a breakage in [2] will only determine the feature responsible; the actual code involved was under development for months prior to that release, that might help guide an investigation.