Blackberry phones: on my history map, the cached locations jump around within a few miles.
Usually the GPS data can drift up to a few hundreds feet but if you see some big jumps and:
1) You are using Blackberry, and
2) The big jumps only happens on the cached records.
Then your phone need a time zone sync:
On your phone, go to the Options page;
Make sure the time zone is set correctly;
Make sure Auto Time Set is Enabled;
Press the track wheel, and Request Time;
Wait for the network activity to complete;
Press the track wheel, and Copy Network Time;
Press the track wheel and Save - exits the Date/Time page;
ESCape back to the main menu.