I am not sure we have the same issue. I have recorded my screen here to demonstrate the issue that I am experiencing with the Bosch Knox and e-Bike Connect not navigating with imported gpx files. The Bosch e-Bike Connect navigates to the start of the gpx route instead of following the trace gpx...
Similar issue with my kiox using saved gpx files. When I select “start route on kiox” it directs me to the starting/ending point of gpx trace, instead of just following the trace of the saved route. Two weeks ago, it was fine. Not anymore. Makes me think it’s a software issue, not a user issue.