Occasionally the mobile Team Data app will need to entirely re-sync. There is nothing wrong with your app or the device.
Please note that following app updates or if you use more than one TeamData account on your device, this will happen the next time you log in.
We strongly encourage you not to log out while your data is syncing, which can take up to a few minutes. This is important to be able to have instant search when you are logged in and to be able to access all of the data in your account when offline.