The most common cause of this, is if you close down the APP. We always recommend that you keep the APP open on your phone, whether that be in the background or on screen whilst actively tracking. Without the APP running, the positions will fail to correctly record. This will also hinder the 'history' section of the APP.
If you find a previous date or time on screen, press 'locate' and wait 40 seconds. Providing the tracker has moved position, the position, time, date and battery percentage, will update.