Our tenant just received the update for new Sharepoint Files experience in Microsoft Teams. It's now possible to "Pin to top", which brings a thumbnail view of the selected item to the top of the library view, as expected.
However, leaving the Files tab and returning to it, the pinned items are no longer visible on top. Opening the library in Sharepoint shows the pinned items correctly there. Alternatively, pinning an item in Sharepoint, does not reflect in Teams.
So it seems the new Teams Files experience is not displaying existing pinned items, it can only display new ones when submitting.
