No fallback to GPS speed after speed sensor disconnects

Today after my speed sensor had disconnected the Instinct 2x Solar did record GPS, time and heart rate but not distance and speed. Auto pause was off and the speed sensor was really disconnected (showing "searching" in the sensor settings) and not only broadcasting 0 values. I would expect that the GPS immediately takes over regarding speed and distance instead of giving me a weird recording that has a perfect track but no distance. Is there some setting that can rectify that in case it happens again? I guess stopping the ride and starting a new one would have helped but I didn't thought of that.