The Last Update field is changing automatically when a end-user clicks in the field, but does not actually make any changes. This will happen if the field is current blank, or if there is data already in the field. This is a change in behavior that is found in versions of GoldMine newer than 9.x.
GoldMine does not detect if the user made a change in the field, it detects if the field was clicked on. Users need to be directed to not click into a data field, unless there they are going to enter new data, or change existing data.