Hi, Alan here, the author of IGCDroid.

Using IGCDroid in a car can produce odd results because your car doesn't move like a glider. Typically gliders don't stop at traffic lights. Using the "Manual" setting for "Recording start/stop mode" should work better.

Glideport.aero also has its own rules about what is required for a flight. It often rejects the very short flights seen when driving.