Piping-hot out of the feature oven!
By default, searches on the Sites page will now be scoped to your currently selected team. Previously, any search term that you entered conducted a global search across all your teams. We found that this change better matches the information architecture of the page, and the expectation of our users.
Global site search found a more logical home in the Command Palette, which can be invoked on any page by selecting the magnifying glass icon in the nav, or by pressing a keyboard shortcut that you define on your user settings page.
If you still yearn for global search behavior on the Sites page, toggle the checkbox that appears to the right of the search field. This checkbox appears only if you are on more than one team.
Enjoy! 