Removing write/modify access of the logged on user to the widevinecdm has seemed to stop the update of 4.10.1146.0 to any higher non-working version. I've had the browser open for over 2 hours playing Netflix and it usually updates by now to a higher version but has not done so since the permissions changes.
In case anyone cares to follow suit.
Not sure how this is going to affect overall functionality, however, since I've noticed nothing out of the ordinary and I've only change permissions on the wide-vine directory and not the whole profile directory I think I'm good.
My idea: Netflix does not detect the browser correct. I can not check as i have no Netflix account
You may start Vivaldi from a desktop shortcut
"C:\Program Files\Vivaldi\Application\vivaldi.exe" --user-agent="Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3602.2 Safari/537.36"
Or try to use extension User-Agent Changer
and add user-agent
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3602.2 Safari/537.36
in section 'Custom User-Agents'.