I have a stock Bugs 2W. In two occasions, I had it go unresponsive and stuck in the air untill the battery died enough to let it fall out of the sky. Both times it was at night. And, both times it was at an undisclosed altitude over 100m but under 400m. Skies were clear. No signs of UFO activity. Other than those two times it flies perfect. I have flown it over 999m with no issues. Is there some night time anomaly that takes place after 10 pm or what? Any thoughts? Oh, serious thoughts.