I can confirm this too. And it is true for Edit Sessions and also for Playtests. Before I was able to quickly join the Edit Session via Social Menu with my second account, but now after update to v36.00 there is no option for that.
If I am not in the party, there is only “Request to Join”, but when I click on it, then I have to confirm it on my first account, but nothing happens when I do that. I need to go to the main screen of a game lobby and click on a yellow button to join the map (Edit Session).
And if I am in the party already, there is nothing to click regarding joining the session. There is only red button “Leave Party” under the name of my first account that started the Edit Session. So even in this case I need to go to the main screen of a game lobby and click on a yellow button to join the map (Edit Session).
So the whole process takes much more time and more clicks then before.