Yesterday I got a notice, that dark mode is now available. Excited, I installed 7.6.
But then Evernote was empty. I logged into the web version (which I haven't visited in a while and I'm glad it's now more like the desktop version) and saw my notes were still there.
Since then, I closed and opened Evernote a couple of times, restarted my Mac, of course I clicked on the sync button
There are now only 3 notes visible on the Mac client and only the tags and notebooks associated to those notes. They were only visible, after I accessed them in the web app.