The earlier Tomtoms have serious issues with the docking stations.
From the pictures it looks like they are using the same solution.
The problem is that the docking station doesn't lock down the GPS unit solid.
It allows it to wiggle.
In a street application this might be OK, but any offroading and this wiggling will get you into problem.
The docking station has a number of spring loaded pins that transfer power and signal to the GPS. The GPS has an equal number of receiving plates.
The wiggling will make the pins wear against the plates until there is a hole in them, and very erratic contact.
I have also been through 3 docking stations since they stopped delivering power.
The plates in the GPS are attached directly to the circuit board and not a spare.