Depending on how much drift there is it may be a fixed offset caused by the timer not restarting until you have finished puttin gin al the settings. You set the time, then do all the the other settings for a couple of minutes, then exit settings and the timer starts from the time you set, in other words wto minute slow. The apparent drift will be short and fairly consistent, and will not increase with time (it is a bias). The solution is to leave the time setting to last and exit set p immediately after you enter the time.

If it is genuine drift then you can correct for it to an extent by noting the time on the camera and on an accurate timepiece when you retrieve the images. If you want to get fancy  you can take an image of a GPS screen with the time on it, and compare it to the time stamp on the image.