Navigation lagging behind actual position

[Next Stop]

Hi all,
Does anyone else have a problem where the position shown on the map whilst driving lags behind your actual position?
When I am at a junction the map seems to show that I am still 20 meters or so away from the actual junction.
When sitting still it seems to catch up.
I've tried a couple of devices and they both seem the same and my other mapping program I use doesn't have this problem.

Cheers,
Martin