It happens in YouTube videos which I open via FireFox add-on "VLC YouTube Shortcut". There are usually 3 times that first there is the popup of "view verification" etc, then "accept permanently" etc; so together its 6 popups. I accept permanently every time. Because of ...
The rest of the default speeds sound fine: 1.5, 2, 4; and at 8 - there's no sound anymore (and no problem with that).
The only default speed with a problem is 3x.
Most small increments also cause this problem - more or less frequently.
How can I do that? I don't see a way to upload here.
Actually I see now that the issue is not global. I just downloaded 2 videos from YouTube in the same languages, and everything worked. So it's only in some files.