Priority for traffic sign recognition?

Why does the permitted speed in the navigator proceed in front of the permissible speed detected by the camera? Within the village (50km/h) the permissible speed on a federal road has been increased to 70km/h in several places. In Würzburg I have the “problem” that above the place sign a limitation is mounted to 60km/h. There the sign is not displayed and the vehicle shows further 100km/h. What indicates, It would make sense that the camera has priority, then both cases would be solved correctly, wouldn’t it?