I was worried at first but it hasn't really affected the flight itself. But then again, I never fly at low, tree and obstruction filled altitudes. Also, if I stop the bird, within secomds the green comes back. This, also, supports my power delivery to the GPS sensor theory. This used to bug me in the past but one phantom later and I stopped worrying. GPS lock at start-up is crucial. Below is a 15 degree celsius flight where there are no GPS issues. The same flight at around 1 celsius and the yellow safe to fly non GPS will show up. Unless I go straight up with no forward movement.