Adding a new board to a workspace does not automatically sync the board to the mobile clients. I have tested both adding a board and a folder to the board and neither change is synced to the client. If I kill the app on the mobile device and then start it again, the new board will display, but not until I do this. Other changes sync to the client without issue once the board is setup, but I expected new boards to sync to the client as well, but this is not happening.
UPDATE: I have done some additional testing. The board will sync when you open a different board and it syncs the data for that board. However, if you are in the dashboard waiting for the board, it will never be synced to the device. There does not appear to be a way to sync the dashboard, by saying pulling down to do a refresh.