Whelp, I just lost all my tabs in all my workspaces except for one in @zenbrowser. And looking through their issue tracker, it seem that similar things are pretty normal.
Just a heads up. I would maybe not use it too much, or recommend it to people, before these issues have been closed: https://github.com/zen-browser/desktop/issues/?q=is%3Aissue%20state%3Aopen%20lost%20tabs