This is unfortunately a quirk of the Working Title GNS430/530 logic.

The logic behind the autopilot controls on the EFB is deliberately very basic to minimise the likelihood of compatibility issues with the various GPS units. We are applying very little (if any) custom logic to the autopilot controls and once they are pressed, they simply trigger the respective autopilot control assignments in the simulator.

Therefore any weird logic quirks like the one you have reported are linked to the GPS units themselves. There are some fixes/improvements expected in Sim Update 15 relating to the Working Title GNS430/530 which may change/improve this behaviour.

Mark - Just Flight

@Thor_999 said in Buxton/Peak Forest Extension:

I've just bought the Buxton/Peak Forest extension. When i selected a quickdrive route from Tunstead Quarry to Leicester, there is a problem with the wagons that have been placed in the sidings at Tunstead. They block the tunnel mouth so that you cannot leave the sidings where you start this quickdrive journey.

Sounds like what I saw and mentioned up thread about the same starting point. I think you can delete the offending wagons via the editor as a workaround.