Hello, Francois ,
Our application works with the data that your tracker sends in messages.
We are not saying that this situation is normal, but most likely the problem is in the accuracy of the GPS signal from your device.
Also keep in mind that many devices have settings for sending more accurate data, check the instructions for your device. For an explanation of the situation and assistance in setting up the device, it is best to contact the manufacturer or seller of the device.
You can also write to us at firstname.lastname@example.org, indicating the login and unit ID, then we can check it additionally.