Was test flying my p2 last week over some deserted fields. I’ve got my right switch set to manual so the only way to initiate RTH is to switch off the tx. I tested this during the flight. It went into RTH, came back at 20m high & hovered over the home point - all good so far. At this point I decided to switch the tx back on & re acquire it. The lights on the p2 went back to green but it did not respond to any tx inputs. After a short time it just auto landed (about 5metres north of home) & switched off the motors. I couldn’t even switch them back on with the tx when stood next to it?? What went wrong?