I had some problems when people signed up, they were logged into the main site dashboard, and then when they went to their own site, they could not use the visual/frontend editor.
A staff from the SLS team fixed this, thread.Fantastic. BUT, this leads to another problem
Once new user signs up for a site, it create new Pro Site registration page on the main site
Please see this video with detailed step
After a user creates a new site, the new pro site registration page is:
While before it was https://domain.com/pro
What I did, was after I saw the issue, I made the URL the same again "/pro" and then added the site to the front page menu again. Then created a new user account, and saw the same thing happen - again