Hello again.
I don't know if this is related to my earlier problem, but Vivaldi has suddenly logged me out of everything again. This time I didn't even close Vivaldi or shut down my computer. A message showed up, saying that Sync was Disabled, and I could find details about this issue in the Sync Settings, yet, accessing the Sync Settings only brought up the Sync section of the settings, allowing me to log back in, with no extra details.
Pop-up message: "An issue caused Vivaldi Sync to stop working. You can find more details in the Sync Settings."
Fortunately, logging in to Sync allowed me to get back synced data, except for the cookies, meaning I had to painstakingly relog into every platform I was l logged in to before.
I am using Windows 10, Vivaldi 5.5.2805.44 at the time of the log-out (about 15 minutes ago)
(5.5.2805.48 as of now)
I have Vivaldi only on this single PC.
Since this is the second time an issue like this has happened, I am once again asking for any help in fixing Vivaldi randomly logging me out of my profile.