The other thing that might be confusing in this update is that the launcher had a bug where when it closed for update, it didn’t actually close because there was a hanging thread in the background.
That meant the undead launcher had exclusive hold over the settings files and so when the updated launcher started it seems to have forgotten your accounts. If you kill all launcher instances from the task manager and start it again, all your accounts are back.
Unfortunately, because it’s a problem with closing the launcher, and you have to close the launcher to patch, the issue happens one last time in the process of rolling the fix out 