Your organizations are listed in the same order every time

The list of organizations at the top of the sidebar came back in an order nobody chose, and it could look different the next time you opened a page. It's sorted by name now, the same order your account already uses.

If you hadn't picked an organization yet, the app used to open the oldest one you joined, and it now opens the first one on that list. The organizations page describes the menu and where to find it in each app.