Unfortunately, I got this problem after activating Beta: Use Unicode UTF-8 for worldwide language described here:
After deactivating Unicode UTF-8, everything worked normally with the navigation! So I use the previously described solution:
To delete the 4files. User / name / AppData / Local / Packages / Microsoft.FlightSimulator_8wekyb3d8bbwe / LocalState / MISSIONS / Custom / CustomFlight / CUSTOMFLIGHT.FLT & .FSSAVE & .PLN & .SPB