OK Model Pilot QB2500 ESC Trouble

A really nice februari day, light winds, great for some soaring. After a short climb out the motor suddenly stopped and made a strange noise. In the video you can also hear the ESC beeping for some reason. I am still trouble shooting the issue, and it hasn't returned. Very strange indeed. The ESC is a Roxxy BL-Control 720 S-BEC rated at 30A, the motor is a Roxxy C28-34 on a SLS 3S2200mah lipo spinning a 10x6 Graupner CAM folding prop. All well within the equipments limitations. If anybody has an idea, please chime in.