Sometimes if i have a double client login running, my characters will get out of sync.

This time:
One driver, one passenger in a rhino. Driving one zone will be fine, after synching my first logged in character will be out of sync. He can still drive anywhere withing the zone, but does not really move the car (which will be at the base position after the sync line).
If the first character logged in then jumps out of the car, it will reset the character to the original position (where my second character was the whole time without being moved).

Personal fix:
Relog.